THIET KE BAI GIANG - f.libvui.comf.libvui.com/dlsm12/ThietKeBaiGiangVatLi12NangCao_a858975d6e.pdf · - Sua't die d6nng tao bdi may phat dien xoay chieu cung co bidu thiic dang nhu

TRAN THUY HANG - HA DUYEN TUNG

THIET KE BAI GIANG

NANG CAO TAP HA!

NHAXUATBANHANOI

TRAN THUY HANG - HA DUY£N TUNG

THIET KE BAI GIANG

lAVt NANG CAO - TAP 2

^ V- ? NHA XUAT BAN HA NOI

CHWONG V. DONG DIEN XOAY CHIEU •

BAI26

DONG DifiN XOAY CHlfiu

MACH DifiN XOAY CHlfiu CHI CO DifiN TRO T H U A N

I-MUCTlfiU

1. Ve kie'n thiic

- Nam ducfc khai niem dong di6n xoay chiû va di6n ap xoay chiû. Biet each xac dinh ,d6 l6ch pha gii5a dien ap va circfng do dong didn xoay chieu theo biû thiic hoac theo do thi biû di6n chiing.

- Nam duoc cac dac didm cua doan mach xoay chieu chi co di£n trd thu^n.

~ Nam duoc cac gia tri hi6u dung va each tinh cong suat toa nhi6t trung binh cua dong di6n xoay chiû.

2. Ve ki n ing

- Ren luyen ki nang quan sat GV tid'n hanh thi nghiem co sit dung dao d6ng ki dien tif, tit do riit ra cac k6't luan cua bai hoc.

II-CHUXNBI

Gido vien

- Chu^n bi mo hinh may phat dien xoay chi6u va dien k6'.

- Dao d6ng ki dien tir, ngudn dien xoay chiû hoc sinh, may phat am tan.

Hpc sinh

- On lai cac kiah thiic ve dinh luat Om va hien tucmg cam ling di6n ttr da hoc 6 ldp 11 THPT.

Ill - THI^T Kf HOAT D 6 N G DAY HOC

Hoat d6ng cua hoc sinh Trd giup cua giao vi#n

Hoat ddng 1 Kiem tra, chu^n b| dieu kien xuat phat HS suy nghl ca nhan tim cau tra Icri - Khi tiir thong qua mat gicfi han boi mach dien km bien doi theo thcfi gian.

- Khi do, goc a bi6'n thi6n theo th6i gian, suy ra ttr th6ng qua mat gi6i han bcri khung day kin bia'n thien theo thcfi gian. Vi vay trong day xua't hi6n m6t suat difen dong cam ling.

- Quan sat tha'y kim cua dien ke dao dong sang phai roi sang trai m6t each tu^n hoan. Chiing to su^t dien d6ng trong khung day bi^n thi6n tudn hoan.

HS tiep thu, ghi nhd

GV neu cau hoi kidm tra kien thiic cu - Hi6n tuong cam utig di6n tix xay ra khi nao ?

- Khi cho khung day quay deu trong tit trucmg vdi t6'c do goc co nhu hmh ve sau day, trong khung co sua't hi6n sua't di6n dong cam ling khong ? Tai sao ?

- Yeu cû HS quan sat GV tien hanh thi nghi6m v6i mo hinh may phat dien xoay chieu co noi v6i dien ke G, sau do dua ra nhan xet ve gia trj cua suat dien d6ng cua may phat dien xoay chieu ? GV thong bao - Sua't diSn dong xua't hien trong khung day bie'n doi theo thcfi gian theo dinh luat dang sin, thucmg goi tat la sua't di6n d6ng xoay chieu : e = EQ cos(cot + (po).

- Chu ki va tSn s6' cua bien doi cua suat di6n dong lien he vdfi tan so goc co bdi

. , „ 271 „ CO

cac cong thuc: 1= — , i = CO 2n

- Sua't dien d6ng tao bdi may phat dien xoay chieu cung co bidu thiic dang nhu tren.

Hoat dong 2

Tim hieu dien ap xoay chieu va dong dien xoay chieu

- Khi do, trong mach co dao d6ng dien cudng biic vdi t^n sd ciia suat dien d6ng do may phat di6n xoay chieu tao ra. Giua hai dSu d o ^ mach cd m6t dien ap bi6'n thi6n theo thdi gian theo dinh luat dang sin.

HS quan sat GV tia'n hanh thi

nghiem vdi dao dong ki dien tu

- Do thi cua didn ap tren hai dû

mach dien cd dang hinh sin.

Hoat ddng 3

Tim hieu dien ap va cudng do

dong di^n ciia doan mach chi c6

dien trd thuan

GV neu cau hoi dd HS tim hidu dien ap

xoay chieu

- Neu ndi hai cue cua may phdt dien xoay chidu vdi mot doan mach ti6u thu di6n thi dien ap giiia hai ddu doan mach cd bidu thiic nhu tha' nao ?

GV neu cac cau hoi goi y

- Nhan xet gi vd dao dOng dian trong

mach tiau thu ?

- Lam thi nghifm nghiem nhu th6' nao dd kidm tra ?

GV tien hanh thi nghiem va yfeu eiu HS quan sat dd nit ra nhan xet

GV thdng bao

- Trong trudng hop t6ng quat, bidu thiic cLia dien ap gifia hai dau doan mach xoay chidu AB va cudng dd dong dian qua nd cd dang :

u = UoCos(cot + (p])

i = lQCos(cot + (p2)

- Dai luong cp = cpj -cpj goi la do lach

pha cua u so vdi i.

Na'u cp > 0 thi u sdni pha so vdi i.

Neu (p < 0 thi u trd pha so vdi i.

Na'u <p = 0 thi u dong pha vdi i. '

GV nau cau hoi dd HS tim hieu dien ap va cudng do ddng dien cua doan mach chi cd dien trd t hu^

HS thao luan ehung toan idp

Ap dung dinh luat Om cho doan

mach :

i = — = —^ cos cot = If, cos cot. R R ^

Cudng do ddng dien tren dien trd

thudn bien thian dong pha vdi dian

ap giua hai dû dien trd va cd bian

dd xac dinh bdi: IA = —- • 0 j ^

Hoat dong 4

Tim hieu mot sd gia trj hieu

dung

HS thao luan ehung toan ldp

Cdng sua't toa nhidt tiic thdi dugc

xac dinh:

p = Ri^= RIQ cos^ «t

Rio 1^0 -, . => p = —y. + —y- cos 2cot.

2 2

Nhiet lucmg toa ra tran dien trd

t h u ^ trong khoang thdi gian t la :

2

- Dat mdt dian ap xoay chieu

u = UQ cos (cot) vao hai ddu doan mach

chi cd dien trd thudn R thi cUdng dd

ddng dien trong mach cd bieu thiic nhu

tha' nao ?

GV nau cac cau hoi goi y

- Xet nhung khoang thdi gian rStt nhd,

dian ap va cudng dd ddng dien coi nhu

khdng ddi, cd thd ap dung dinh luat Om

cho doan mach nay duoc khdng ?

- Nhan xet gi ve do lach pha giua dian

ap va cudng do ddng dien trong mach ?

GV nau cau hdi dd HS tim hidu ve cac

gia tri hieu dung

- Khi cho ddng dien xoay chieu chay

qua dien trd thudn se lam cho dien trd

toa nhiet. Nhiet lucmg toa ra tran dien

trd trong khoang thdi gian t duoc xac

dinh nhu the nao ? Cudng dd ddng dian

khdng doi chay qua dien trd phai cd gia

tri bang bao nhiau dd nhiat luong toa ra

khdng doi trong ciing khoang thdi gian t ?

GV nau cac cau hdi goi y

- Tai thdi diem t, cdng suat toa nhiat

tren dien trd duoc xac dinh nhu the nao ?

- Cdng suat toa nhiet trung binh duoc

; xac dinh : p = p = RIQ COS^ cot = — - •

; Nhiet luong toa ra trong thdi gian t

; duoc xac dinh nhu tha' nao ? 1

- Khi cho ddng I kh6ng d6i chay qua dian trd thudn thi nhiat lucmg toa ra tran dian trd :

Q = Klh^l = ^ . V2

,-

HS ti^p thu, ghi nhd

- Ndu cho cudng dd ddng dian khdng d6i I chay qua dian trd trong cung khoang thdi gian t sao cho nhiat lucmg toa ra la khdng ddi thi I phai cd gi^ tri bang bao nhiau ?

GV thdng bao - Dai lucmg I dvtac goi 1 cudng dd ddng dien hiau dung ciia ddng dian xoay chidu. - Cudng dd ddng dian hiau dung ciia ddng dien xoay chidu bang cudng dd cua mdt ddng difn khdng ddi, ndu cho hai ddng dian dd Idn lupt qua ciing mdt dian trd trong nhttng khoang thdi gian bang nhau du dai thi nhiat lupng toa ra bang nhau.

- Tuong tu nhu vay, ngudi ta cung x^c dinh dupe suSt dian ddng hiau dung cfia

mdt ngudn dian xoay chidu : E = - j ^

va dian ap hiau dung d hai ddu doan

mach xoay chieu : U = ~^' V2 .

- Dd do dien ap hiau dung va cudng do ddng dian hieu dung cua ddng dien xoay chidu, ngudi ta diing vdn k^ va ampe ke xoay chidu.

Hoat ddng 5

Bieu dian cudng do dong dien xoay chieu va dien ap xoay chieu b^ng vecta quay


GV nau cau hdi dd HS bidu diln cudng dd ddng dian xoay chidu va dian ap xoay chidu bang vectcf quay - Hay nau each bieu didn cudng dd ddng dian i va dian ap u bang cac veclo quay ? Nhftn x t gi ve hai veclo I,U cua doan mach chi cd dian trd thudn ?

- Bidu didn cudng do ddng dien i va dien ap u bang cac vecto quay

tucfng ling I,U cd dd clai ti la vdi cac gia tri hiau dung U, I va quay ngupe chidu kim ddng ho quanh gd'c O vdi tde do gde bang tan so goc CO cua ddng dien. d thdi diem ban ddu t = 0, chiing cd phucmg hpp vdi true Ox mot gde bang pha ban ddu cua dai lupng tucmg ling.

- Tran gian dd Fre-nen cho doan mach chi cd dien trd thudn, cac

vecto quay I, U cd ciing hudng.

Hoat ddng 6

Ciing cd' bai hoc va dinh hudng nhiem vu hoc tap tiep theo

GV yau cdu HS lam bai tap trac nghiam trong phia'u hpc tap de cung cd bai hpc

- HS ve nha lam cac bai tap 1, 2, 3, 4 SGK.

- HS dn tap lai cac kidh thiic vd ddng dian xoay chidu.

PHlfiU HOC TAP

caul. Cho mdt khung day dSn phang cd dien tich S quay deu vdi tde dd gde CO quanh mdt true vudng goc vdi cac dudng siic cua mdt tii trudng ddu

cd cam ling tii B. Trong khung day se xua't hian

A. hien tupng tu cam.

B. sua't dian ddng cam ling.

C. ddng dien mot chieu.

D. sua't dian dong tu cam.

Cau 2. Cudng dp ddng dien va dien ap ciia mdt ôan mach xoay chidu cd dang

i = IQ sin(cot + —) ; u = Ugsin(cot — ),k4 luan nao sau day diing khi ndi 3 6

vd dp lech pha ciia didn ap so vdi cudng c^ ddng dian ?

n A. Dian ap trd pha hcfn cudng dp ddng difn mdt goc cp = —

Ad

B. Dian ap sdm pha hon cudng dd ddng îen mdt goc cp = — •

C. Dian ap va cudng dp ddng dian ddng[)ha. 71 D. Dien ap trd pha horn cudng dp ddng 6^tn mpt goc cp = —

6

Cau 3. Cho mach dien nhu hinh ban, cap bidi

thiic nao sau day bidu didn cudng c5 ddng dien va dian ap ciia doan mach '

A. i = locos(cot-7c) ;u = UoCOs(cot + 7J).

B. i = IoCos(cjOt);u = UoCos(cot + 7t).

C. i = IoCOs(cot);u = Uosin(cot).

D. i = IQ sin(cot + —); u = UQ cos (cot).

Cau 4. Cho dong dian xoay chidu i = locoscot chay qua dien trd thudn R.

Biau thiic nao biau didn cdng sua't toa nhiat tiic thdi tran dien trd R sau day sai ?

-2 A. p = Ri

Ri; C. p = —^cos2cot.

2

5. p = Rlocos^cot.

RIn RI§ „ , -cos2a)t.

cau 5. Cho cudng dp ddng dian xoay c;pieu i = Iosino)t chay qua difn trd

thudn trong thdi gian t. Na'u chb cudng dp ddng dien khdng doi I

chay qua dian trd thudn dd trong thdi gian t thi cudng dp ddng dien

khdng ddi nhan gia tri nao trong cac gia tri sau day de nhiet lupng

toa ra tran dian trd thudn d hai trudng hpp la nhu nhau ?

9

A. I = Io. B. I = V2lo.

C I = i - D. 1 = ^ . V2 2

Cau 6. Cho cudng dp ddng lian xoay chidu chay qua mdt doan mach la i = 2sinl00t (A). Cudig do ddng dian hiau dung nhan gia tri nao trong cac gia tri sau day ? A. I = 2A. B. I = IA.

C. I = 4A. D. 1= V2A.

10

BAI27

MACH DifiN XOAY CHIÛ CHI CO TU DifiN, CUdN CAM

I-MUCTlfiU

1. Vi ki 'n thiic

- Hidu dupe cac tac dung cua tu dian va cupn cam trong mach dian xoay chidu. - Tim dupe bieu thiic cudng dp ddng dien qua tu dien bang li thuya't. - Dd xudt dupe phucmg an thi nghiem vdi dao ddng ki dien tii de nghien ciiu su bien ddi ciia cudng dp ddng dien qua mach dian cd tu dien va dien ap giiia hai ban tu dien theo thdi gian. - Tim dupe bieu thiic dian ap giila hai ddu cupn cam bang li thuyet. - Di xua't dupe phucmg an thi ngiiiem vdi dao ddng ki dien td de nghian cihi su bien ddi cua cudng dp ddng dien qua mach dien cd cupn cam va dian ap gifla hai dau cupn cam theo thdi gian. " Nam dupe khai niem dung khang, cam khang. Bie't each tinh dung khang, cam khang va ve gian dd Fre-nen cho doan mach chi cd tu dien va doan mach chi cd cupn cam.

2. \ i ki nSng

- Ren luyen ki nang dd xua't va thia't ka' thi nghiem de nghian cihi su bia'n ddi cua cudng dp ddng dian va dian ap theo thdi gian cua doan mach chi cd tu dien va doan mach chi cd cupn cam. - Ren luyen ki nang quan sat giao vian tie'n hanh thi nghiem, tir dd nit ra ke't luan. - Ren luyen ki nang ve gian dd Fre-nen cho doan mach chi cd tu dien va doan mach chi cd cupn cam.

II-CHUXNBI

Giao vien

- Dao dong ki dian td, bang mach dian chi cd tu dian, bang mach dien chi cd cupn cam, may phat am tdn, bia'n thd hpc sinh loai 0 - 12V.

Hoc sinh

- 6n tap lai cac kid n thiic vd ddng dien xoay chieu.

11

Ill - THifiT Kfi HOAT D 6 N G DAY HOC

Hoat ddng cua hoc sinh

Hoat ddng 1

Ki^m tra, chudn b| dieu kian xuat phat

HS suy nghl ca nhan tim cau tra ldi

HS nhan thiic dupe va'n dd cua bai hpc

Hoat ddng 2

Nghien ciiu gia tri turc thdi cua

cudng dp ddng dian va dien ap

cua doan mach xoay chieu chi cd

tu dien. Ve gian do Pre - nen.

HS thao luan nhdm, sau dd dai dian nhdm lan bao cao ket qua

- Dian tich tran ban M d thdi didm t i a :

q = Cu = CUQ sin cot

- Cudng dp ddng dien:

i = —i = CcoUn cos cot dt "

=> i = IQ cos (Ot, vdi IQ = CCOUQ .

TrO giup cua giao vi§n

GV nau cau hdi kidm tra kien thiic cu - Ve gian dd Fre-nen cho doan mach chi cd dian trd thudn ? Nhan xet vd dp lech pha cua dien ap giiia hai ddu dien trd thudn vdi cudng dp- ddng dian qua doan mach chi cd dian trd thudn ?

Dat vdn de : Trong mach dian xoay chidu, ngoai dien trd thudn, ta con gap hai loai phdn td khae la tu dien va cupn cam. Chiing cd tac dung gi ddi vdi mach dien nay ? Bai hoc ngay hdm nay giiip chiing ta tra ldi cau hdi dd.

GV nau cau hdi vd va'n dd edn nghian cuu

— Dat vao gifla hai ban tu dien M va N mpt dien ap xoay chidu u = Uosincotthi cudng dp ddng diari

trong mach cd bieu thiic nhu tha' nao? Nhan xet gi ve dp lach pha gifla cudng dp ddng dian so vdi dian ap gifla hai ban tu ?

C 1 1

M N

A B

' V

12

Mat khae, ta ed

u = UQ sin cot => u = Un cos '0 tot — 2

vay dien ap gifla hai ban tu dian trd pha hem so vdi cudng dp ddng

dien trong mach m5t gde —.


- Cdn mpt mach dian chi ed tu dian. Dian ap dat vao mach dian dupe la'y d may bie'n ap hpc sinh. Dian ap tran hai ban tu dipn dua vao cdng CHI ciia dao dpng ki dien td.

- Mac ndi tiep mpt dien trd vao mach dian, dua dian ap tren hai ddu tu dien vao edng CH2 ciia dao dpng ki dd nghian cuu cudng dp ddng dian trong mach.

HS chii y Idng nghe va cjuan sat

GV nau cac cau hdi gpi y

- Xac dinh dian tich tran ban M eiia tu

dian d thdi didm t ?

- Na'u quy udc chidu duong ciia ddng

dien la chieu til A tdi M thi cudng dp

ddng dian trong mach dupe xac dinh

nhu tha' nao ?

GV nau cau hdi thiat kd phucmg an thi nghiem.

- Hay thie't ka' phuong an thi nghiam kidm tra ke't qua chiing ta vtra tinh dupe bang con dudng li thuyet ?

GV*nau eac cau hdi gpi y

- Dao dpng ki dian td chi do true tiep dian ap, lam tha' nao dd do dupe cudng dp ddng dien trong mach ?

- Ta da biet cudng dp ddng dien qua dien trd thudn ddng pha vdi dian ap tran hai ddu dien trd, lieu rang cd thd mac mpt dien trd thudn nd'i tie'p vdi tu dien va dua dien ap cua dien trd vao dao dpng kf dien tit thay cho viae nghian ciiu cudng dp ddng dian trong mach dupe khdng ?

GV tia'n hanh lap rap va gidi thieu thi nghiem ma HS viia thia't ka'

V S ^ l"^ •-Mpp

13

HS quan sat va riit ra ka t luan

- Cudng dp ddng dien qua tu dipn

bia'n thien sdm pha so vdi dian ap

71 gifla hai ban tu dien mpt gde —

HS lam viec ca nhan, sau dd thao

luan ehung toan ldp

- Tai thdi didm t = 0, ve vecta

quay I bidu didn cudng dp ddng

dian i = IQ eos cot hpp vdi true Ox

mpt gde bang 0, vecto quay U^ ;

bidu didn dien ap

u = Uo cos ^ n^ cot —

2 hpp vdi tnjc

TT Ox mpt gde —

O

U,

- Mac mach dian nhu hinh ve tran bang

mach : R= 5,lkO. C = 0,01^xF

GV yau cau HS quan sat dd thi ciia dien

ap va cudng dp ddng dian trong mach

tren man hinh dao dpng ki dian tii, sau

dd riit ra ket luan vd dp lach pha gifla

dien ap va cudng dp ddng dien.

GV yau cau HS ve gian dd Fre-nen cho

doan mach ehi ed tu didn

Hoat ddng 3

xay dung bieu thiic dinh luat

6 m ddi vdi doan mach cd tu

dien. Tim hieu khai niem dung

khang.

HS thao luan ehung toan ldp.

GV nau cau hdi vd vdn dd cdn nghian

ciiu

- Dai luong trong cong thiic coC

IQ = CCOUQ ed y nghia gi ?

14

- Chia bidu thiie cho N/2, ta dupe :

Zc gifl vai trd nhu dien trd ddi vdi

ddng dian khdng ddi.

HS thao luan theo nhdm, sau dd dai dian nhdm lan bao cao ket qua

- Sii dung thi nghiam vdi dao ddng ki dian tii nhu d tran. Ldn lupt thay ddi gia tri dien cua tu dian va tdn sd cua dian ap dat vao hai ddu doan mach. Quan sat su bien ddi cua cudng dp ddng dian trong mach tren man hinh dao dpng ki dian tii.

HS quan sdt GV ti^n hanh thi nghiem, tii dd rut ra nhan xet.

- Khi gia tri dipn dung ciia tu dipn tang thi gia tri bian dp ciia cudng dp ddng dien tran man hinh dao dpng ki dian tii tang. Didu dd chiing to dung khang ciia mach giam. Suy ra dung khang ti la nghich vdi dian dung ciia tu dian.

- Khi gia tri tang tdn sd ciia dien ap dat vao hai ddu tu dien thi gia tri bian dp ciia cudng dp ddng dien tran man hinh dao ddng ki dien tii tang. Didu dd chiing td dung khang


- Dat Zc = —V- va chia hai v^ ciia bidu foC

thiic cho ^/2 bidu thiie tran dupe via't nhu the nao ? - So sanh bieu thiie viia xay dung vdi bidu thirc dinh luat Cm cho doan mach chi cd dien trd thudn, tfl dd cho biai y nghia cua XQ ?

GV nau cau hdi thia't ka' phucmg an thi nghiam - Hay thia't ka' phucmg an thi nghiam dd

minh hoa cdng thiic Zp = va nau coC

each tia'n hanh thi nghiam ?

GV ti^n hanh thi nghiam, yau cdu HS quan sat va nit ra kdt luan

- Tang gi^ tri dian dung ciia tu dian, yau cdu HS hay nhan xet su phu thupc cua dung khang vao dian dung ciia tu dian?

- Tang gia tri tdn sd ciia dian ap dat vko hai ddu tu dien bang may phat am tdn, yau cdu HS hay nhan xet su phu thupc cua dung khang vao tdn sd goc co ?

15

ciia mach giam. Suy ra dun'g khang ti la nghich vdi tdn so cua dien ap hay ti le nghich vdi tdn sd gde eiia dian ap dat vao hai ddu tu dien.

Hoat ddng 4

Nghien cihi gia tri turc thdi ciia cudng dp ddng dien va dien ap trong doan mach xoay chieu chi cd cupn cam. Ve gian do Fre -

nen

HS thao luan theo nhdm, sau dd dai dien nhdm lan bao cab kdt qua

Khi cd ddng dien bidn thian theo thdi gian chay qua cupn day thi trong cupn day xua't hien sudt dian ddng cam ling:

e = - L — ^coLIrtSincot dt ^

Quy udc chidu ddng didn chay tir A tdi B la chieu duong. Dien ap gifla hai diem A va B la:

u = iRAB-e

Vi cupn day thudn cam nan R^g cd

gia tri bang khdng. Nan :

GV nau cau hdi vd vdn dd cdn nghian

ciiu

- Gia sit tai thdi diem t cudng dp ddng

dien xoay chieu i^locoscot chay qua

doan mach ehi ed cupn cam cd dp tu cam L theo chidu tii A den B, hay tim bidu thiic cua dian ap tran hai ddu cupn

cam ?

L

—nmm^—

- ^ - ^ A B


- Hian tupng gi xay ra khi ed ddng dian

bia'n thian chay qua cupn cam?

- Sudt dien dpng tu cam tran cupn cam dupe xac dinh nhu tha' nao?

- Theo dinh luat Om, dien ap tran hai ddu cupn cam dupe xac dinh nhu tha' nao?

- Nhan xet gi vd dp lech pha giiia dien ap tran hai ddu cupn cam vdi cudng dd ddng dien chay qua cupn cam ?

16

u = - e = -coLlQsincot

=:>U = UoCOS eot + —

vdi UQ =COLIO.

Cudng do ddng dian qua cupn cam thudn cam bien thian dieu hoa vdi

7U

Cling tan sd nhimg tra pha hon —

ddi vdi dian ap gifla hai ddu cupn

cam.


- Cdn mdt mach dien chi cd cupn cam. Dian ap dat vao mach dien dupe la'y d may bia'n ap hpc sinh. Dian ap gifla hai ddu cupn cam dupe dua vao cdng CHI cua dao dpng ki dian t^.

- Mac ndi tidp mot dien trd vao mach dian, dua didn ap tran hai ddu tu dien vao cdng CH2 ciia dao ddng ki dd nghian ciiu cudng dp ddng dien trong mach.

HS quan sat GV tie'n hanh thi

nghiam va nit ra ka't luan

- Quan sat tran man hinh dao dpng

ki dien tii ta thdy ka't luan tim dupe

bang con dudng li thuyet d tran la

hoan toan diing.

GV nau cau hdi thi^t k^ phucmg ap thi

nghiem

- Hay thia't k€ phuong an thi nghiem va trinh bay each tien hanh tiii nghiem dd

kidm tra k^t luan d tran ?

GV tia'n hanh lap rap va gidi thieu thi nghiem ma HS viia thiet ka'

- Thi nghiam cdn cd: R = 5,lkQ,

cupn day L : 3000 vdng (ed loi sdl).

GV tia'n hanh thi nghiam, yau cdu HS quan sat va rut ra kat luan

TKBGVL#12/2(NC) 17


T X \ h h I

0 :

Tran gian dd vecto Fre - nen cho | doan mach chi cd cupn cam thudn, [

— - n ' U lap vdi I mpt gde — theo ;

chidu duong. '•

Hoat ddng 5

Xky dung bieu thiic dinh lu$t ; Om ddi vdi doan mach co cupn :

cam thu^n. Tim hieu khai niem i

cam khang

HS thao luan ehung toan ldp \

- Chia bidu thiie eho v2 , ta dupe \

I u : i ^L 1

ZL gifl vai trd nhu didn trd ddi vdi ;

ddng dien Ichdng ddi. :

HS thao luan theo nhdm, sau dd i dai dian nhdm lan bao cao ket qua ;

- Sii dung thi nghiem vdi dao dpng i ki dien tir nhu d tran. Lan lupt thay • ddi gia tri L cua cupn cam va tdn sd' ;

GV yau cdu HS ve gian dd Fre-nen eho

doan mach chi ed cupn cam

GV nau eau hdi vd vaii dd cdn nghian cihi.

- Dai lupng coL trong cdng thflc

UQ = COLIQ ed y nghia gi ?


- Dat Z L = coL va ehia hai vc ciia bidu

thiic cho v2 bidu thflc tran dupe viet

nhu tha' nao ?

• - Sc) sanh bieu thiic viita xay dung vdi

; bidu thiie dinh luat 6m eho doan mach • chi cd dien trd thudn, tfl dd cho biet y

; nghia cua ?

i GV nau cau hdi thiet ka' phuang an thi ; nghiam

: - Hay thia't ke phuong an thi nghiem dd

: minh hoa cdng thiic ZL = coL va nau

'. each tia'n hanh thi nghiem ?

18

cua dian ap dat vao hai ddu doan mach. Quan sat su bia'n ddi ciia cudng dp ddng dien trong mach tran man hinh dao dpng ki dian tii.

HS quan sat GV tia'n hanh thi

nghiam, tfl dd nit ra nhan xet.

- Khi gia tri L ciia cupn cam tang

thi gia. tri bian dp ciia cudng dp

ddng dien tren man hinh dao dpng

ki dian tir giam. Didu dd ehiing td

cam khang cua mach giam. Suy ra

diing khang ti le thuan vdi dp tu

cam cua cupn cam.

- Khi gia tri tang tdn sd eiia dian

ap dat vao hai ddu cupn cam thi

gia tri bian dp ciia cudng dp ddng

dien tran man hinh dao dpng ki

dian tu giam. Didu dd chiing td

cam khang cua mach giam. Suy ra

dung khang ti le nghich vdi tan sd

cua dien ap hay ti le nghich vdi tdn

sd gde ciia dien ap dat vao hai ddu

cupn cam.

Hoat ddng 6

Ciing cd bai hpc va dinh hudng nhiem vu hpc tap tiep theo

GV tia'n hanh thi nghidm, yau cdu HS

quan sat va riit ra ket luan

- Tang gia tri L eiia cupn cam bang

each cho tham ldi sat vao cupn cam, yau

cdu HS hay nhan xet su phu thupc cua

cam khang vao dp tu cam L eiia cupn

cam ?

- Tang gia tri tdn sd eua dian ap dat vao

hai ddu cupn cam bang may phat am

tdn, yau cdu HS hay nhan xet su phu

thupc cua cam khang vao tdn sd gde co ?

GV yau cdu HS lam bai tap trdc nghiem

trong phia'u hpc tap dd cung cd bai hpc

- HS vd nha lam cac bai tap 1, 2, 3, 4, 5, 6 SGK.

- HS dn tap lai eac kia'n thirc vd ddng dian xoay chieu.

19

PHlfiu HOC T^P

C&u 1. Cho mach dian nhu hinh ve, k^t luan C

nao sau day la diing khi ndi vd sd chi | U" cua ampe ke trong mach dian ?

A. La gia tri eiia cudng dp ddng dian hieu dung

B. La gia tri bian dp eiia cudng dp u ddng dien

C. La gia tri tiic thdi cua cudng dp ddng dien

D. Ampe ka' chi sd 0 vi tu dipn khdng cho ddng didn chay qua

CAu 2. Dat vao hai ban cua tu dipn mdt dien ap xoay chidu uÛpsincot,

cudng dp ddng dien chay qua tu dien la

A. i = CUQCOs(cot). B. i = coCUoCos ' , n cot+—

V 2

C. i = coCUosin(cot). D. i^coCUpsin cot + — .

CAu 3. Tang tdn sd gde eua dien ap dat vao tu dien ga'p 2 ldn thi dung khang

cua tu dien se

A. tang ga'p 2 ldn. B. giam 2 Idn.

C. tang gap 4 ldn. D. khdng thay ddi.

CAu 4. Ngudi ta dat mpt mach dipn trong mpt hdp kin cd hai ddu day ndi ra ngoai. Bia't rang mach dien chi sir dung mpt trong 3 linh kian didn trd thudn R, tu dien C, cupn cam L thudn cam hoac gdm 2 trong 3 linh kian tren mdc ndi tiep. Bang thuc nghiem tha'y rang cudng dp ddng dien trong mach ciing pha vdi diari ap dat vao hai ddu mach dian. Mach dian dMqc cdu tao bdi

A. R mdc ndi tia'p vdi C. B. L mac ndi tia'p vdi C.

C. chi cd L. D. chi cd R.

20

BAI28

MACH CO R, L, C M A C N 6 I TifiP. CdNG HUONG DifiN

I - M U C T l £ u

1. \ i kid'n thtic

- Biet each ve va dung gian dd Fre - nen dd nghian ciiu doan mach ed R, L, C mdc ndi tidp.

~ xay dung dupe eae edng thflc tinh tdng trd Z, d6 Itch pha giua dian ap va cudng dp ddng dian, bidu thflc dinh luat 6m. Ap dung cae cdng thflc dd dd lam mpt sd bai tap don gian.

- Nam dupe hien tucmg cpng hudng dian va didu kidn dd xay ra hian tupng cdng hudng dien.

- Dd xua't va thia't ka' dupe phuong an thi nghipm nghian cflu hien tupng cpng hudng dian.

2. Ve ki ndng

- Ren luyan ki nang dd xudt va thia't k^ thi nghiam dd nghian cflu hidn tupng cpng hudng dian.

- Ren luypn ki nang quan sat giao vian tien hanh thi nghiem, tfl dd rut ra ket luan.

- Ren luyan ki nang ve gian dd Fre - nen cho doan mach R, L, C mac ndi tidp.

II-CHUXNBI

Giao vien

- Dao dpng ki dian tfl, bang mach dipn ehi ed tu didn, bang mach dian ehi cd cupn cam, may phat am tdn, bi^n tha' hpc sinh loai 0 - 12 V.

- Chudn bi phia'u hpc tap eho HS.

Hoc sinh

- On tap lai cac kian thuc va doan mach xoay chidu chi ed didn trd, ehi cd tu dian, chi cd cupn cam thudn.

- Phucmg phap gian dd Fre - nen.

71



Hoat ddng 1

Kiem tra, chuan b| dieu kien xua't phat. Dat van de


HS nhan thflc dupe van de cua bai hpc

Hoat ddng 2

Nghien ciiu doan mach R, L, C mac ndi tiep

HS chu y Idng nghe

Trp giup ciia giao vi^n

GV nau cau hdi kidm tra kia'n thflc cu - Vie't bieu thflc dian ap ciia doan mach chi cd dien trd thudn, chi ed cupn cam, ehi ed tu dien ? Nhan xet gi vd dp lach pha eua cac dian ap so vdi cudng dp ddng dian chay trong mach ?

Dat va'n dd : Doan mach xoay chidu ed ca ba loai phan tfl (dien trd, cupn cam, ; tu dian) mdc ndi tie'p cd mpt sd dac tinh khae vdi doan mach dien xoay chieu chi cd mpt loai phdn tu. Khi ta tang ddn mpt thdng sd nao dd eua mach, ching han nhu dien dung cua tu dien, cudng dp ddng dian cd thd tang rdi giam. Bai hpc ngay horn nay diing phucmg phap gian dd Fre - nen de nghian cuu doan mach R, L, C mac ndi tiep.

GV gidi thieu doan mach R, L, C mdc ndi tia'p.

- Doan mach gdm mpt dian trd thudn R, mpt cupn cam thudn cd dp tu cam L va •mpt dien dung C mac ndi tia'p. Ta gpi doan mach dd la mach RLC ndi tia'p.

R L c

^ L 1—•—'75?R5OTr —•-A 1 # A M N B

GV nau eau hdi ve vdn dd cdn nghian cflu

22


- Trong mach cd dao dpng dien cudng bfle vdi tdn sd gde bang tdn sd gde cua dien ap. - Bidu thflc cua dian ap tfle thdi tran cac phdn tfl R, L, C eua doan mach RLC hdi tia'p la

Up = u^^^ =IoRcoscot = UoCOSCot

UL = COLIQ cos(cot + —)

= UoLCOs(cot + - )

Ur = _ 0 71,

coC cos(cot—)

71. = Uoccos(cot--)

Vi cac phdn tfl trong mach mdc nd'i tie'p nan dien ap tfle thdi gifla hai ddu doan AB la

U = U , t+UL+Uc

Bidu didn cae dien ap tran cung mpt gian dd Fre - nen ta dupe :

î + ^c

O

u

1

luc

-- S

—•• P

X

- Dat vao hai ddu A, B cua doan mach

mpt dien ap xoay chidu u ed tdn sd

gde CO. Hien tupng gi xay ra trong doan

mach ? Gia sfl cudng dp ddng didn chay

trong doan mach cd bieu thflc

i = IQ COS cot thi bidu thflc cua dian ap d

hai ddu doan mach cd dang nhu the nao ?

GV neu cac cau hdi gpi y

- Hien tupng gi xay ra trong doan mach ?

- Vidt bidu thflc eua dian ap tran cac phdn tu cua doan mach RLC ?

- Cac phdn tfl trong mach dupe mdc nhu tha' nao ? Dian ap tfle thdi hai dau doan mach cd quan ha nhu thd' nao vdi dian ap tran mdi phdn tfl cua doan mach ?

- Sfl dung phuang phap nao dd tim bidu thflc tdng quat eua dien ap tran hai ddu doan mach ? Cd thd su dung phucmg phap gian dd Fre - nen dupe khdng ?

- Hay bidu didn dien ap tren mdi phdn tu tren ciing mpt gian dd Fre - nen ?

- Mudn tim dupe dian ap tran hai ddu A, B ta phai tim vecto nao ?

23

Tacd:

U = U R + O L + U C

=>U = Ûi+(UL-Uc)^

TT ,T coL U L - Up fiir tancp= ^ *- ^^^

U R

Khi coL> thi tancp>0, dian coC H ' -

ap sdm pha hon so vdi cudng dp ddng dian.

Khi coL < thi tan cp < 0, dian coC Y , .

ap trd pha hon so vdi cudng dp ddng dian.

vay bidu thflc cua dien ap tran hai ddu AB cd dang :

u = Uv2 cos (cot + cp)

Trong dd U = ^ U ^ + ( U L - U C ) ^

1 roL-

tan<p =

Thay

coC R

I UR = I R ; U L =I(»L;UC = vao

coC bieu thflc xac dinh U, ta dupe :

U 1 =

R + O)L-coC

- Xae dinh dp lach pha cua didn ap tran hai ddu A, B so vdi cudng dp ddng dian trong mach ? Tfl dd eho bidt khi mio dian ap gifla hai ddu A, B trd pha va sdm pha so vdi cudng dp ddng dian trong mach ?

- Tim bidu thflc dinh luat 6m cho doan mach RLC ndi tia'p ?

24

HS tia'p thu, ghi nhd

GV thdng bao

Dat Z = jR^+(coL—— coC

, gpi la

tdng trd cua mach RLC ndi tia'p.

Bidu thflc cua dinh luat 6m khi dd dupe

Viet: I = — Z

Hoat ddng 3

Nghien cihi hien tupng cpng hudng dien HS thao luan ehung toan ldp - Cudng dp ddng dian phii thupc vao R, L, C va co. - Tfl bidu thflc dinh luat 6m, ta

thdy khi coL = 0, thi cudng coC

dp ddng dian trong mach dat gia

tri cue dai I ax = — Khi dd, R

cudng d6 ddng dian cue dai chi phu thude vao dipn trd thudn R ciia doan mach.

-Khi ©L = 0 thi tancp = 0, coC ^

cudng dp ddng dien trong mach va dian ap ddng pha. HS thao luan ehung toan ldp - Cdn mpt mach dian RLC mdc ndi tidjp. Dien ap dat vao mach dien dupe la'y d may phat am tdn. Dian ap tran hai ddu doan mach dua vao cdng CHI ciia dao dpng ki dian tfl.

GV nau cau hdi vd vdn de cdn nghian cflu - Gifl nguyan gia tri c;ua dian ap hieu dung gifla hai ddu doan mach, cudng dp ddng dian trong mach phu thupc vao nhihig yeu td nao ? Khi nao cudng dp ddng didn trong mach dat gia tri cue dai ? Nhan xet gi vd dp lach pha giua dien ap tran hai ddu doan mach va cudng dp ddng dien chay trong mach ?

GV nau cau hdi thia't ka' phuong an thi nghiem - Hay diiat ka' phucmg an thi nghiam kidm tra ke't luan tran ?

25

- Mac ndi tia'p mpt dien trd vao mach dien, dua dian ap tran hai ddu tu dien vao cdng CH2 eua dao dpng ki dd nghian cflu cudng dp ddng dian trong mach.

- Ldn lupt thay ddi gia tri R cua dian trd, L eua cupn cam, C cua tu dien va tdn sd cua dien ap dat vao hai ddu doan mach. Quan sat su bia'n ddi eua cudng dp ddng dien trong mach tr6n man hinh dao dpng ki dian tfl, quan sat dp lech pha cua cudng dp ddng dian va dien ap khi cudng dp ddng dian cue dai, quan sat su phu thupc cua cudng dp ddng dien cue dai vao R khi R thay ddi.

HS quan sat GV tia'n hanh thi nghiem va nit ra ket luan

- Khi L thay ddi, cudng dp ddng dien trong mach thay ddi. Khi cudng dp ddng dian trong mach dat gia trj cue dai thi nd ddng pha vdi dien ap tran hai ddu doan mach.

GV gidi thiau thiai bi thi- nghiem va tidn hanh thi nghiem, yeu cdu HS quan sit

va nit ra ka't luan.

- Thi nghiem thay ddi L.

- Tfl tfl dich ehuydn ldi sdt dd thay ddi dp tu cam L eua cupn day, quan sat su thay ddi cua do thi ddng dien tran man dao dpng ki dien tfl, xae dinh vi tri eua ldi sat dd xay ra cpng

26

- Thay ddi R, gia tri cue dai cua dong dien thay ddi ti le nghich vdiR.

- Khi C thay ddi, cudng dp cidng dian trong mach thay ddi. Khi cudng dp ddng dien trong mach dat gia tri cue dai thi nd ddng pha vdi dian ap tran hai ddu doan mach.

- Thay ddi R, gia tri cue dai cua ddng dian thay ddi ti le nghich vdiR.

- Khi f thay ddi, cudng dp ddng dian trong mach thay ddi. Khi cudng dp ddng dien trong mach dat gia tri cue dai thi nd ddng pha vdi dien ap tran hai ddu doan mach.

- Thay ddi R, gia tri cue dai ciia ddng dian thay ddi ti le nghich vdiR,


hudng cua mach, chflng td su cue dai eua ddng dian va su ddng pha eua nd vdi dien ap ?

- Thay ddi R, quan sat su phu thude ciia cudng dp ddng dien cue dai vao R ?

- Thi nghiam thay ddi C.

- Thay ddi dian dung C cua tu dien, quan sat su thay ddi cua dd thi ddng dian va dien ap tran man dao dpng ki dien tfl, xac dinh vi tri epng hudng ciia mach, chflng td su cue dai eua ddng dien trong mach va sy ddng pha ciia nd so vdi dian ap ?

- Thay ddi R va quan sat sy phu thupc eua cudng dp ddng dian eye dai v a o R ?

- Thi nghiam thay ddi f.

- Thay ddi tdn sd cua dien ap tfl may phat am tdn dua vao mach, quan sat sy thay ddi cua dd thi ddng dian va dien ap tren man dao dpng ki dien tu, xac dinh vi tri epng hudng cua mach, chflng td sy eye dai cua ddng dian trong mach va sy ddng pha eua nd so vdi dien ap.

- Thay ddi R va quan sat sy phu thupc ciia cudng dp ddng dian eye dai vao R.

GV thdng bao

- Hien tupng ta thu dupe d tran, khi

coL = Othi cudng do ddng dian coC

trong mach dat gia tri cue dai

27

Hoat ddng 4

Ciing cd' bai hpc va djnh hudng nhiem vu hpc tSp tie'p theo

max = ~' gpi la hian tupng epng R

hudng dien.

GV yau cdu HS lam cac bai tap trong phia'u hpc tap de cung c6 bai hpc

- HS lam bai tap vd nha 1, 2, 3, 4 SGK.

- HS 6n tap lai edng thflc tinh cong sudt tiau thu ciia mach dian mpt chidu.

PHifiu HOC T^P

Cau 1. Quan sat tran gian do Fre - nen, ban Anh rut ra cac ket luan dudi day. Theo em ka't luan nao dung ?

A. U ^ U R + U L + U C -

B. U O = U R + U L + UC.

U,+Uc

o

C. Un=Unp+Um +U

I

1

lo.

u

^

I

- . < ;

'P x

'OR OL 'OC-

D. U = U R + U L + UC.

cau 2. Dipn ap tran hai ddu doan mach R, L, C mdc ndi tia'p va cudng dp ddng dien chay trong mach dupe bieu didn tran gian dd Fre ~ nen nhu hinh ban. Ket luan nao sau day la dung khi ndi ve dian ap tran hai ddu cupn cam va dien ap trdn hai ddu tu dien ?

A. U L = U C . B. U L > U C .

C U L < U C . D . U L = U C = 0 .

Cau 3. Neu doan mach xoay chidu chi ed L va C mdc ndi tiep thi tdng trd cua doan mach se bang

28

A. Z = coL- B . Z = COL-coC

1 C. Z = coL +

coC

cau 4. Cho doan mach nhu hinh ve.

D. Z = \ GoL-

R L

A M

Tdng trd cua doan mach la:

A. Z = JR^ +

B. Z = j R ^ +

coL-1 1

OOC] Ci)C2

C. Z = . R^ +

D. Z = . R' + c o L — ^ coC \)

Cau 5. Cho doan mach nhu hinh ve.

L.

(oC

1

coC

C, C,

N

•^000000^

B

B

Tdng trd eua doan mach la

A. Z = coLi +C0L2.

C. Z = L,+Lo.

B. Z = coL] -a>L2.

D. Z = + coL] o)L2

CAu 6. Cudng dp ddng dien ludn luOn trd pha hon dien ap d hai ddu doan

mach khi

29

A. doan mach chi ed cupn cam C.

B. doan mach cd R va C mdc ndi tia'p.

C. doan mach cd L va C mdc nd'i tia'p.

D. doan mach cd R va L mac ndi tia'p.

CAu 7, Khi cd hian tupng epng hudng xay ra trong mach R, L, C mdc ndi tiep thi ka't luan nao trong cac ket luan sau day sai ?

A. Cudng dp ddng dien hieu dung trong mach dat gia tri ldn nha't.

B. Dien ap tfle thdi d hai ddu doan mach cung pha vdi dian ap tfle thdi d hai ddu dien trd R.

C. Dien ap hieu dung d hai dau dien trd nhd hon dien ap hieu dung d hai ddu doan mach.

D. Cam khang va dung khang cua mach bang nhau.

Can 8. Didu kien de xay ra hien tupng epng hudng trong mach R, L, C mdc nd'i tia'p la

A. C = 4 - - B. co= ^ VL • VLC

C. C = ^ - D. L - ^ 'Leo VcoC

Cau 9. Trong mpt hop kin cd chfla mpt mach dien gdm hai phan tfl mdc ndi tia'p. Khi dat vao hai ddu doan mach mpt dien ap xoay chidu cd gia trj hieu dung la lOOV thi dien ap hipu dung gifla hai ddu phdn tfl 1 la

100N/2V, giua hai dau phdn tfl 2 la 200V Hai phdn tfl 1 va 2 tucmg

flng la

A. tu dien va cupn day khdng thudn cam.

B. tu dien va cupn day thudn cam.

C. dien trd thudn va tu dien.

D. dien trd thudn va cupn day.

30

BAI29

C 6 N G SUXT CUA DONG DifiN XOAY CHlfiu Hfi sd C6NG SUXT

I-MUCTl£U

LVe'ki^n thflc

- Nam dupe dac diem cua cdng suat tfle thdi, cong suat trung binh.

- Nam dupe khai niam ha sd edng sudt va y nghia eiia nd. - Biet each ap dung cae cong thflc dd lani mpt bai tap trdc nghiem khach quan nhieu lya chpn.

2. Vi ki n5ng

- Ren luyan ki nang logic toan hpc de xay dung cac bidu thflc cua cae dai lupng vat li.

- Ren luyen ki nang lam bai tap trac nghiem khach quan nhidu lya chpn.

II-CHUXNBI

Giao vien

- Chudn bi phia'u hpc tap cho HS.

Hoc sinh

- HS on tap lai cdng thflc tinh cdng sudt tiau thu cua mach dien mpt chieu.

Ill - T H I £ T K£' HOAT D 6 N G DAY HOC


Hoat dong 1

Kiem tra, chuan hi dieu kien xuat phat


Trp giup cua giao vi§n

GV neu cau hdi kidm tra kie'n thflc cu - Xae dinh cdng sudt tiau thu cua mpt doan mach ed dian ap hai ddu doan mach la U va cudng dp ddng dian mpt chieu chay qua doan mach la I ?

31

HS nhan thflc dupe vdn dd cua bai hpc

Hoat ddng 2

Tim hieu cdng suat tiic thdi va

cong suA't trung binh


Ta ed p = ui

= Uoloeoscot.eos(cot + cp)

=> p = UI2.eoscot.cos(cot + cp)

- UI cos cp + UI cos (2cot + cp)


Dat vdn de : Ddi vdi doan inach mpt chidu, na u dung ampe kd do cudng dp ddng dipn I va vdnk^ do dipn ap U gifla hai ddu mpt doan mach, ta xac dinh dupe cdng sudt tiau thu dian cua doan

mach theo cdng thflc ^ = UI. Ddi vdi cac doan mach xoay chidu ndi ehung, neu chi dung vdnkd va ampe k^ de thuc hian hai phep do U va do I, ta chua thd xae dinh dupe edng sua't tiau thu dien cua doan mach. Vi sao lai cd sy khae nhau dd? Bai hpc ngay hdm nay giup ehung ta tra ldi cAu hdi dd.

GV nau eau hdi dd HS tim hidu edng sudt tfle thdi

- Cdng sudt tfle thdi la cdng sudt tiau

thu dian eua mach dipn d mdi thdi didm

va dupe xac dinh bang p = ui. Nd u mpt

doan mach cd ddng didn i = locoso)t

va dien ap hai ddu doan mach

u = UoCOs(a)t + cp) thi cdng sudt tfle

thdi dupe xac dinh bang bidu thflc nao?

GV thong bao

- Cdng sudt trung binh cua ddng dian tinh trong khoang thdi gian t la dai lupng xae dinh bang cdng thflc

W ^ = Trong dd W la dian nang da

tiau thu tran doan mach trong khoang thdi gian t.

32

- Cdng sudt trung binh cua ddng dien trong mpt chu ki gpi tat la cdng sudt cua ddng dian xoay chieu. Cdng suat cua ddng dien xoay chidu trong doan mach l aS^ = UIeoscp.

Hoat ddng 3

Tim hieu y nghia cua he sd cdng sua't

HS thao luan ehung toan Idp

- Dya vao gian dd Fre-nen cua doan mach RLC nd'i tia'p, ta ed:

UR R coscp = — ^ = —

• U Z



- He sd cong sudt cd gia tri tfl 0

ddnl.

GV nau cau hdi dd HS xay dung bidu thflc tinh ha sd edng sudt

- Dai lupng coscp trong bidu thflc tinh

cong suat cua ddng dien xoay chidu gpi la ha sd cdng suat. Hay xac dinh he sd cdng sudt dd ?

GV th6ng bao . - Ngoai each sfl dung gian dd Fre - nen, ta cd thd xac dinh he sd cdng sudt bang lap iuan sau; Doi vdi doan mach RLC ndi tia'p, dien nang chi tiau thu tran dien trd thudn R. Vay cdng suat cua ddng dian xoay chidti bang edng sudt toa nhiet tran R. Suy ra:

•y R

S^ = UIcoscp = R I => coscp = — •

GV nau eau hdi dd HS tim hidu y nghia cua ha sd edng sudt

- Nhan xet gi ve gia tri eOa he sd cong sudt ? Khi nao he cdng sudt dat gia tri cue dai ?

TKBG VLyi2/2(NC) 33

- He sd cdng suat dat gia tri eye

dai coscp - 1 khi trong doan mach

xay ra hian tupng cpng hudng dien.

Ucoscp

sudt giam thi cudng dp ddng dian

trong mach phai tang dd cdng sudt

tiau thu khdng thay ddi. Khi dd

hao phi vi nhiat tran day ddn se

ldn. Dd la dieu nan tranh.

Hoat ddng 4

Cung cd' bai hpc va dinh hudng nhiem vu hpc tap tie'p theo

— Nhan xet gi vd su hao phi dian nang tran day ddn khi he sd cdng sudt giam. Bie't rang cdng sudt tieu thii tran doan mach va dipn ap hai ddu doan mach khdng thay ddi ?

GV yau cdu HS lam cac bai tap trdc nghiam trong phia'u hpe tap dd eung cd kien thflc

- Lam cac bai tap vd nha 1, 2, 3,4 SGK.

— 6 n lai khai nipm tfl thdng va dinh luat cam flng dian tfl d ldp 11 THFT; cac kien thflc ve ddng dien xoay chidu va may phat dian xoay chidu d ldp 9 THCS.

PHlfiu HOC T^P

Cau 1. Ket luan nao sau day la dung khi ndi vd cdng sudt tfle thdi cua ddng dian xoay chidu ? A. Cdng sua't tfle thdi luon la mpt hang sd. B. Cdng suat tfle thdi bien thidn didu hoa theo thdi gian. C. Cdng sudt tfle thdi bi^n thien tuy^n tinh theo thdi gian. D. Cdng su^t tfle thdi bien thian theo quy luat ham sd mu.

can 2. Ndu trong doan mach xoay chieu cd ddng dian I = I,2cosl007rt(A) thi cdng sua't tfle thdi bien thian didu hoa vdi tdn sd A. 50Hz. B. lOOHz. C. 150Hz. D. 200Hz.

34

c a u 3. Ha so cdng sudt dat gia tri ldn nhdt khi

A. trong mach xay ra hian tupng epng hudng dien.

B. tdn sd cua dien ap dat vao hai ddu doan mach dat gia tri ldn nhdt.

C. tdn sd cua dian ap dat vao hai dau doan mach dat gia tri nhd nhdt.

D. nhiat lupng toa ra trong mach nhd nhdt.

cau 4. Ha sd cdng sua't cua ddng dian xoay chidu nao trong cac doan mach

dudi day ed gia tri bang 0 ?

A. Mach dien chi cd dien trd thudn.

B. Mach dien ehi ed cupn cam thudn.

C. Mach dien gdm dian trd thudn va tu dien mac ndi tiep.

D. Mach dien gdm dian trd thudn va cupn cam thudn mdc ndi tiep.

cau 5. Ka't luan nao sau day dung khi ndi vd sy anh hudng cua he sd cdng

sudt dd'i vdi sy hao phi dian khi truydn tai dian nang di xa ?

A. Ha sd cdng sudt cang ldn thi hao phi dian nang cang ldn.

B. He so cdng suat cang ldn thi hao phi dien nang cang nhd.

C. Ha sd cdng sudt cang ldn thi hao phi dian nang khdng thay ddi.

D. Sy tang hoac giam eua hp sd cdng sudt khdng anh hudng den sy

hao phi dian nang.

c a u 6. Dat mpt dien ap xoay chidu u = 220V2 sin(lOOcot) (V) vao hai ddu

doan mach R, L, C khdng phan nhanh ed dien trd thudn R = lOOfi. Khi ha sd cdng sudt cua doan mach ldn nhdt thi cdng sudt tiau thu eua doan mach la

A. 284W. B. 384W.

C. 484W. D. 584W.

cau 7. Mpt tu dian ed dian dung C = 5,3pF mdc ndi ti^p vdi dian trd R = 3 0 0 0 .

Doan mach dupe dat vao mang dien xoay chidu 220V - 50Hz. Hp sd cdng sudt cua doan mach la

A. coscp«0,147. B. coscp« 0,247.

C. coscp « 0,347. D. coscp a; 0,447.

35

BAI30

M A Y P H A T DifiN XOAY CHIÛ

I - MUC TifiU

1. \ i kie'n thflc

- Hieu dupe nguyan tde hoat dpng eua may phat dien xoay chidu.

- Nam dupe cdu tao cua may phat dian xoay chidu mpt pha va ba pha.

- Bia't van dung cac cdng thflc dd tinh tdn sd va sudt dien dpng cua may phat dian

xoay chidu.

2. Ve ki nang

- Ren luyen ki nang dn luyan kien thflc cu.

- Ren luyan ki nang md ta va nau nguyan tde hoat dpng cua cae flng dung ki thuat

vat li.

- Ren luyen ki nang lam eae bai tap trie nghiam khach quan nhidu lua chpn ve

may phat dien.

I I -CHUXNBI

Giao vien

- Mo hinh may phat dien xoay chidu 1 pha va eae hinh ve may phat dian xoay

chidu 1 pha va 3 pha.

- Ve hinh 30.1; 30.2; 30.4 SGK tran gidy khd AQ.

- Phia'u hpc tap.

Hoc sinh

- 6n lai khai niem tfl thdng va dinh luat cam flng dian tfl d ldp 11 THPT; cac kidii

thflc ve ddng dien xoay chidu va may phat dien xoay chidu d ldp 9 THCS.

36

m - THifiT K6 H O A T D O N G DAY HOC

Hoat ddng cua hoc sinh Trp giiip cua giao vi^n

Hoat ddng 1

Kidm tra, chuin bi dieu kian xu^t phat. Dat van de


- Khi cd sy bien ddi tfl thdng qua mat gidi han bdi mpt mach kin thi trong mach xudt hien mpt ddng dian cam flng.

- Tfl cdng thflc <I> = BSeosa, suy ra cac each lam bien ddi tfl thdng la: lam thay ddi cam ling tfl B, lam thay ddi dien tich S eua khung day, lam thay ddi gde a.

- Do ldn cua sudt dian dpng cam flng trong mach kin ti la vdi tde dp bia'n thian cua tfl thdng qua mach

e, = -N At

- Khi AT -> 0 thi sudt dien ddng cam flng dupe xae dinh

e =-N ' dt

- May phat dian xoay chidu ed hai bp phan chinh la nam cham va cupn day ddn. Mpt trong hai bp phan dd dflng ydn gpi la stato, bp phan cdn lai la rdto.

GV nau cau hdi kidm tra kien thflc cu

- Trinh bay hipn tupng cam flng dien tfl ?

- Trinh bay cac each lam bien ddi tfl thdng qua mat gidi han eua khung day ?

- Phat bidu dinh luat Fa-ra- day vd cam flng dien tfl ?

- Khi AT -> 0 thi sudt dien dpng cam flng dupe xac djnh nhu the nao ?

- Nau cdu tao va hoat dpng cua may phat dien xoay chidu da dupe hpe d ldp 9THCS?

Dat vdn de : May phat dien la eac thia't bi dung de bien ddi co nang thanh dien nang. Trong bai nay, ta xet hai loai may

37

HS nhan thflc dupe vdn de cua bai hoc

phat dien xoay chidu thudng dung va tim hidu ki hon vd nguyan tde hoat dpng cung nhu cdu tao cua may phat dien ?

Hoat ddng 2

Tim hieu nguyen tac hoat dpng cua may phat dien xoay chieu


- Nguyan tde hoat dpng cua may phat dian xoay chidu dya tran hian tupng cam ling dien tfl. Khi tfl thdng qua mpt vdng day bia'n thian didu hoa, trong vdng day xudt hian mpt sudt dian ddng cam flng xoay chidu.

- Suat dien dpng xoay chieu trong cupn day la:

e = -N do dt

= 27ifN<I>o sin cot

( n e = 27rfN<I>A cos cot —

" ' 2 e = En cos

' 7t^ cot —

2

Vdi EQ = 27TfNOo la bian dp eua

sudt dian dpng cam flng.

- Cd hai each dd lam cho tfl thdng bidn thian qua cac vdng day trong may phat dien:

+ De tfl trudng cd dinh, cho eae vdng day quay trong tfl trudng. + De tfl trudng quay, cae vdng day dat CO dinh trong tfl trudng quay dd.

GV nau cau hdi dd HS tim hidu nguyan tde hoat dpng cua may phdt dien xoay chidu

- Hay nau nguyan tde boat dpng cua may phat dian xoay chidu? Ndu tfl thdng qua mdi vdng day kin bien thian <!)] =BScoscotthi sudt dien dpng cam

ihig trong khung day N vdng dupe xac dinh nhu tha' nao ?

- Trong cae may phat dien, ngudi ta thudng lam tha' nao dd cd tfl thdng bidn thian qua cac vdng ddy ?

38

Hoat ddng 3

Tim hiû cû tao va hoat dpng cua may phat dien xoay chieu mpt pha


HS thao Iuan ehung toan ldp

- So dd I ed phdn flng quay va phdn cam ed dinh. So dd 2 ed phdn ihig ed dinh va phdn cam quay.

- May phat dian xoay chieu mpt pha cd thd hoat dpng theo hai each

Cdch 1 : phdn flng quay, phdn cam cd dinh.

Cdch 2 : phdn cam quay, phdn flng cd dinh.

- Dd ddn ddng dian ra mach ngoai, ngudi ta dung hai vanh khuyan dat ddng true va cung quay vdi khung day. Mdi vanh khuyan cd mpt thanh quet ti vao. Khi khung day quay, hai vanh khuyan tnrpt tran hai thanh quet, ddng dian truydn tfl khung day qua hai thanh quet ra ngoai.

GV thdng bao

- Ldp 9 THCS, ehung ta da hpc : May phat dien xoay chidu cd hai bp phan ehinh la nam cham va cupn day ddn. Mpt trong hai bp phan dd dflng yan gpi la stato, bp phan cdn lai la rdto.

- Bp phan chinh : nam cham (cd the la nam cham dian hoac nam cham vinh cflu) gpi la phdn cam. Dd la phdn tao ra tfl trudng.

- Bp phan ehinh : cac cupn day gpi la phdn flng, trong dd sudt hidn sudt hien sudt dian dpng cam flng.

GV yau cdu HS quan sat hai hinh ve 30.1 va 30.2 SGK tran gidy khd A^ va tra ldi cau hdi

- Hai hinh ve la so dd may phat dian xoay chidu mdt pha. Hay cho biat sy khae nhau vd cdu tao cua hai may phat dien ? Tfl dd eho bia't cac each hoat dpng cua may phat dian xoay chieu mdt pha?

Dd'i vdi each hoat dpng thfl nhdt, dd dua ddng dian ra ngoai thi phai lam nhu tha' nao de cac day ddn khdng bi xoan ?

39


Hoat ddng 4

Tim hieu ve may phat dien xoay

chieu ba pha

GV thdng bao

- Cac may boat dpng theo each thfl hai ed rdto la nam cham, thudng la nam cham dien dupe nudi bdi ddng didn mpt chidu ; stato gdm nhidu cupn day cd ldi sat, xep thanh mpt vdng trdn. Cae cupn day roto cung cd loi sdt va xep thanh vdng trdn, quay quanh true qua tam vdng trdn.

- Di tang sudt dian dpng cua may phat, phdn flng thudng gdm nhidu cupn day, mdi cupn lai gdm nhidu nam cham dian tao thanh nhidu cap eye Bde - Nam, bd tri lach nhau sao cho mpt phdn flng va phdn cam thudng dupe quan tran cac ldi thep kl thuat dd tang cudng tfl thong qua chflng. Ldi thep gdm nhidu la thep mdng ghep each dien vdi nhau dd giam hao phi nang lupng do ddng Fu-c6.

- Neu may phat cd p cap cue, khi rdto quay mpt vdng, sudt dien dpng se bi^n thian tudn hoan p lan. Gpi n la tde dp quay cua rdto thi tdn sd bian thian f cua sudt dien dpng cua may se la f = pn.

GV thdng bao dinh nghia ddng dipn xoay chieu ba pha

- Ddng dien xoay chieu ba pha la ha

thdng ba ddng didn xoay chieu, gay ra

bdi ba sudt dipn dpng xoay chidu cd

cung tdn sd, cung bian dp nhung Ipch

pha nhau tfl ddi mpt la

40



. • . - • ' f j ' ' .

- May phat dian xoay chidu ba pha

cd cdu tao gidng may phat dien

xoay chidu mpt pha hoat dpng theo

each thfl hai nhimg stato cd ba

cupn day riang re, gidng nhau

quan tran ba ldi sdt dat lech nhau

120** tran mpt vdng trdn. Rdto la

nam cham dian.

- Sudt dien dpng tran ba cupn day

cua may cung bian dp, cung tdn sd

2n nhung lach pha nhau

Na'u chpn gde thdi gian thich hpp thi bieu thflc cua cac suat dian dpng la :

Ci ÊQCOSCOI

e2 =EQCOS cot

(cot + f ) e3 = EQ COS

GV nau cau hdi dd HS tim hieu cau tao may phat dien xoay chidu ba pha

- He thdng ddng dien xoay chieu ba pha dupe Idy ra tfl may phat dien xoay chidu ba pha. Quan sat hinh ve md hinh may phat dien xoay chidu ba pha, md ta cdu tao cua nd va cho biet sy khae nhau vd cdu tao gifla may phat dien xoay chidu ba pha va may phat dien xoay chidu mpt pha ?

- Nhan xet gi ve sudt dien dpng tran ba cupn day cua may phat khi rdto quay ddu ?

41


- Trong each mdc hinh sao : Ngudi ta ndi ba didm cudi eiia ba cupn day vdi day trung hoa rdi ndi ba diem ddu vdi ba dudng day cdn lai cua ha thdng tai dien.

- Trong each mdc hinh tam giac:

Ngudi ta nd'i diem ddu cua cupn

day nay vdi diem cudi eua cupn

day kia (B^ vdi A2, B2 vdi A3, B3

vdi Aj) rdi ndi 3 diem A,, A2, A3

vdi ba dudng day tai dien.

GV thdng bao

- Ndu ndi cac ddu day cua ba cupn day vdi ba tai tiau thu gidng nhau thi ta cd he thdng ba ddng dien eung bian dp,

2n cung tan so nhimg lach pha nhau — •

- Ngudi ta thudng khdng sfl diing ba sudt dien dpng xoay chidu trong ba cupn day cua may phat mpt each dpng lap ma mdc cupn day vdi mach ngoai thanh mpt ha thdng. Cd hai each mdc: mac hinh sao va mdc hinh tam giae. GV yau cdu HS quan sat hinh ve 30.5, 30.6 va nau each mdc hinh sao va each mdc hinh tam giae

B,,62,63


GV thong bdo

- Trong each mac hinh tam giac, dipn

ap hiau dung gifla hai day tai dien U^

42

Hoat ddng 5

Cung cd bai hpc va dinh hudng nhiem vu hpc tap tiep theo

bang dien ap hipu dung d hai ddu mpt cupn day eua may phat dien Up.

- Trong each mdc hinh sao, dien ap ddy va dian ap pha lian he vdi nhau:

Ud=VÛp.

GV yau cdu HS lam cac bai tap trdc nghiam trong phieu hpc tap de cung cd kia'n thflc - Lam cac bai tap vd nha 1, 2, 3,4 SGK. - 6n lai khai nipm tfl thdng va dinh luat cam flng dien tfl d ldp 11 THPT ; cac kiah thflc vd ddng dien xoay chidu va may phat dian xoay chidu d ldp 9 THCS.

PHlfo HOC TAP

cau 1. May phat dian xoay chidu hipt pha hoat dpng dya tran nguydn tde A. hien tupng cam flng dien tfl. B. hien tupng edng hudng dipn. C. hien tupng doan mach. D. hian tupng siau ddn.

Cau 2. Cho cupn day phang cd N vdng quay vdi van tde goc co trong tfl trudng ddu tran mpt true vudng gde vdi cac dudng sfle. Tfl thdng qua mdi vdng day bia'n thian theo quy luat O = OQ eos cot. Bian dp cua sudt dian dpng cam flng xua't hian trong cupn day la

coN A E - ^ ^ .

_coNOo C. b , - ^

B.E. = ^

D. Eo=coN<I>o.

Cau 3. Cach lam nao trong eac each sau day khdng tao ra dupe sudt dien dpng cam flng trong khung day ddn kin ?

A. Cho khung day quay trong tfl trudng ddu.

43

B. Dat khung day trong tfl trudng deu, bdp meo khung day dd thay ddi dian tich S cua khung.

C. Cho khung day chuydn dpng trong tfl trUdng ddu sao eho mat phang khung day ludn vu6ng gde vdi cac dudng sflc.

D. Thay ddi cam flng tfl B eua tfl trudng ma khung day dat trong do. cau 4. Phdn cam ciia may phat dien la

A. phdn chuydn dpng roto. B. phdn dflng yan stato. C. phan tao ra tfl trudng. D. nhung cupn day, trong dd xua't hien sudt dien dpng cam flng.

cau 5. Cach lam nao trong cac each sau day khdng lam tang suat dian dpng cam flng cua may phat dian xoay chidu mpt pha ? A. Tang sd cupn day mdc ndi tia'p cua phdn flng. B. Tang sd cap eye cua phdn cam. C. Tang tde dp quay cua roto. D. Giam sd cap eye eua phdn cam.

cau 6. Mpt may phat dien ed p cap eye. Tde dp quay cua rdto la n vdng/phut. Tdn sd bia'n thian eua sudt dian dpng cua may phat la

A. f = pn. B.f = P^. 60

C. f = ^60. D. f = ^ -n n

cau 7. Ket ludn nao sau day sai khi so sanh may phat dian xoay chidu ba pha va may phat dien xoay chieu mpt pha ? A. Ca hai ddu boat dpng theo nguyan tde hien tupng cam img dien tfl. B. Ca hai ddu cd eau tao gdm phdn cam va phdn flng. C. Ca hai deu cd phdn cam la phdn chuyen dpng, phdn flng la phdn

dflng yan. D. Ddng dien tao ra bdi hai may la ddng xoay chidu.

Cau 8. Ket luan nao sau day dung khi ndi vd dien ap trong each mac hinh tam giac ?

A. Ud=V3Up. B. Ud=Up.

C U d = ^ - D. V3Ud=Up.

44

BAI31

DONG CO KH6NG D6NG BO BA PHA

I-MUCTl£U

1. \ i ki€n thflc

- Hidu tha' nao la sy quay ddng bp va khdng ddng bd.

- Giai thich dflpe nguyan nhan cua sy quay khdng ddng bd trong thi nghiem giao vian tia'n hanh.

- Hidu th^ nao la tfl trudng quay va each tao ra tfl trudng quay nhd ddng dien xoay chidu ba pha. - Nam dupe nguyan tde cdu tao va hoat dpng cua dpng co khdng ddng bd ba pha.

2. V ' ki n3ng

- Ren luyen ki nang quan sat GV tien hanh thi nghiam va rut ra ket luan. - Ren luyan ki nang tim hidu, nghian cflu thia't ka' flng dung ki thuat vat li. - Ren luyan kl nang lam cae bai tap trac nghiem khach quan nhidu lya chpn ve dpng CO khdng ddng bp ba pha.

II-CHUXNBI Giao vien

- Chudn bi cac thi nghiem vd sy quay ddng bp va sy quay khong ddng bp. - Chuan bi phidu hpc tap.

Hoc sinh

- On lai kian thflc vt ddng dien xoay chidu 3 pha.

Ill - THifiT K£' H O A T D 6 N G DAY HOC

Hoat ddng cua hpc sinh

Hoat ddng 1 Kiem tra, chuan hi dieu kien xuat phat. Dat v^n de

Trp giup cua giao vien

GV nau cau hdi kidm tra kien thflc cu

- Viet eac bidu thflc cua cac sua't dien dpng tran cac cupn day cua may phat

45

HS suy nghica nhan tim cau tra ldi

HS nhan thflc dupe vdn dd cua bai hoc

dian xoay chidu ba pha ? Bidu didn sy phu ttiupc cua chflng vao thdi gian tran eung mdt dd thi ?

Dat van di' : Dpng eo dipn xoay chidu ed hiau sudt cao hon dpng co dipn mpt chidu. Mpt im didm ldn cua ddng dien xoay chidu la tao ra dupe tfl trudng quay dung trong cae dpng co dipn xoay chidu. Vay tfl trudng quay la gi ? Tai sao loai ddng eo dien xoay chidu xet trong bai hpc nay gpi la dpng co khdng ddng bp ?

Hoat ddng 2

Tim hieu tiir trudng quay, sir quay ddng bp va SIJT quay khdng ddng bp

HS Ihao luan ehung toan ldp

- Tfl trudng do nam cham gay ra ed cae dudng sfle tfl quay trong khdng gian.


GV nau eau hdi de HS tim hieu vd tfl trudng quay

- Nhan xet gi vd tfl trucftig do nam cham

chfl U gay ra khi eho nam cham quay

quanh mpt true ?

GV thdng bao

- Khi mpt nam cham quay quanh mdt true, tfl trudng do nam cham gay ra cd cac dudng sflc tfl quay trong khdng gian. Dd la tfl trudng quay.

46

HS suy nghl ca nhan, tim cau tra ldi

- Kim nam cham se quay ciing tde dp gde vdi nam cham chfl U.

HS thao luan ehung toan ldp va dua ra dy doan

- Khung day se quay eung tde dp vdi nam cham.

HS quan sat GV tidn hanh thi nghiam va rut ra ka't luan

- Khung day khdng quay cflng tde dp vdi nam cham ma quay vdi tde dp gde nhd hon tde dp goc cua nam cham.

GV gidi thieu thi nghiem ve sy quay ddng bp va tra ldi cau hdi

- Dat mdt kim nam cham trong Idng eua nam cham chfl U, quay ddu nam cham chfl U. Nhan xet gi vd sy quay eua kim nam cham ?

N

GV nau cau hdi dd HS tim hieu sy quay khong ddng bp

- Ndu thay kim nam cham bang mpt khung day kin ed the quay quanh mpt triic thing dflng thi hidn tupng gi xay ra khi quay deu nam cham ?

N

GV tia'n hanh thi nghipm, yau cdu HS quan sat va rut ra kdt luan.

- GV quay nam cham cho den khi nam cham quay ddu va yau cdu HS quan sat nit ra nhan xet.

47

HS thao luan ehung toan ldp dd giai thich hian tupng.

- Khi nam cham quay tao ra tfl trudng quay, tfl trudng quay lam cho tfl thong qua khung day bien thian, trong khung day xudt hien mpt ddng dien cam flng. Cung ehinh tfl trudng quay nay tac dung lan ddng dien trong khung mpt momen lye lam khung day quay.

- Theo dinh luat Len-xo, khung day quay theo chidu quay cua tu trudng dd lam giam tde dp bien thian cua tfl thong.

- Na'u khung day quay vdi tde dp gde bang tde dp gde cua nam cham thi tfl thdng qua khung day khong bie'n thien, ddng cam flng bang khong, khong edn mdmen lye tfl tac dung. Mdmen cam lam cho khung day quay cham lai. Luc dd lai cd ddng cam flng va mdmen luc tfl tac dung vao khung.

- Vay, tde dp gde cua khung day luPn nhd hcfn tde dp goc cua tfl trudng quay.

Giao vian yau cdu HS giai thich hien tupng.

GV nau cac eau hdi gpi y

Hien tupng gi xay ra trong khung day khi nam cham quay ?

- Mdmen cua lye tac dung nao lam cho khung day quay ?

- Theo dinh luat Len - xo thi khung day phai quay nhu the nao de lam giam tde do bia'n thian cua tfl thdng qua khung day ?

- Neu khung day quay vdi tde d6 goc bang tde dp goc eua nam cham thi hian tupng gi xay ra trong khung day ? Tfl dd rut ra ka't luan gi ?

GV the cha' hoa kieh thflc

- Theo thi nghiem I, kim nam cham quay cung tde dp gde vdi tfl trudng. Ta ndi kim nam cham quay ddng bp vdi tfl trudng.

- Ddi vdi thi nghiem 2, nhd cd lac dung cua tfl trudng quay va hien tupng cam

ung dien tfl ma khung day quay vdi tde dp gde nhd hem tde dp gde eua tfl trudng. Ta ndi khung day quay khdng ddng bp vdi tfl trudng.

Hoat ddng 3

Nghien cflu each tao ra tiir trudng quay bang dong dien ba pha

HS thao ludn ehung toan ldp

- Cd thd tao tfl trudng quay bing ddng dien ba pha. Mdc ba cupn day gidng vdi mang dien ba pha. Trong ba cupn day ed ba ddng dian cung bian dp, cung tdn sd

nhung lach pha nhau Mdi

cupn day ddu gay d vung xung quanh O mpt tfl trudng ma cam flng tfl ed phuong ndm dpc theo true cupn day va bidn ddi tudn

GV nau cdu hdi vd vdn dd cdn nghian ciiii.

- Tlieo cac thi nghiam tran, dd tao tfl trudng quay ta phai tac dung co hpc dd quay ddu nam cham quanh mpt true. Liau cd each nao tô tfl trudng quay ma khdng phai tde dung co hpc nhu tran khdng? ^


- Cd the sfl dung tfl trucaig cua ddng dian dd tao ra tfl trudng quay hay khdng ? Nd u cd thi phai sfl dung ddng dian khong ddi hay ddng dien xoay chidu ?

- Cd the sfl dung ddng dian ba pha dd tao ra tfl trudng quay dupe khdng ?

- Neu sfl dung hp thdng ddng dien xoay chidu ba pha dd tao tfl trudng quay ta phai lam thd nao ?

TKBGVLyi2/2(NC) 49

hoan vdi cung tdn sd co nhung lach

pha nhau 3

B] = Bocoscot

8 2 = BQCOS cot

r 2n1 B3 - B Q C O S COtH

- He thdng ddng dipn xoay chidu ba pha dupe dua vao cac cupn day bd tri nhu hinh ve, hay via't bidu thflc cua tfl trudng tao bdi cac cupn day tai tam vdng trdn va bidu didn cac vecto tfl trudng gay ra bdi cac ddng dien tai thdi diem bdt ki ?

- Hay chiing minh tfl trudng tdng hpp gay ra bdi he thdng ddng dian xoay chidu ba pha tai O cd dp ldn khdng ddi va quay trong mat phang song song vdi ba true cua ba cupn day vdi tde dp gde CO ? (Viec chdng minh nay diing cho HS khd, gidi)

GV the che hoa kieh thflc

- Vay, ed thd tao ra tfl trudng quay bang ddng dian xoay chieu ba pha. Vecto

cam ling tfl tdng hpp B eua tfl trudng tdng hpp cd dp ldn khdng ddi va quay trong mat phdng song song vdi ba true cupn day vdi tde dp gde co.

Hoat ddng 4

Nghien ciiu cau tao va hoat dpng cua dpng co khdng dong bp ba

pha


- Dpng eo gdm hai bp phan chinh: Stato ed ba cupn day gidng nhau qudn tran ba loi sdt bd tri lech nhau 1/3 vdng trdn. Rdto la mpt khung day.

GV ndu cau hdi dd HS thiet ka' flng dung kl thuat dpng CO khdng ddng bp ba pha

- 6 tren ehung ta da bia't nhd ed hian tupng cam flng dien tfl va tac dung cua tfl trudng quay ma khung day quay va sinh cdng. Hay thiet k^ mpt dpng co boat dpng theo nguyan tde dd.?

GV nau cac eau hdi gpi y

- Dpng CO gdm eac bp phan nao? Bp phan nao dflng yan ? Bd phan nao chuyen dpng ?

50

GV thdng bao

- Dpng CO hoat ddng theo nguyan tde tran la dpng eo khdng ddng bp ba pha.

- Trong thuc ta', Rdto ta mpt hinh tru tao bdi nhidu la thep mdng ghep lai. Trong cac ranh xe d mat ngoai rdto cd dat eae thanh kim loai. Hai ddu mdi thanh dupe ndi vao cac vanh kim loai tao thanh mpt chia'e Idng. Ldng nay each dien vdi ldi thep va cd tac dung nhu nhidu khung day ddng true dat lach nhau. Rdto ndi tren gpi la rdto long sdc.

- Khi mdg- cae cupn day d stato vdi nguda 4ian ba pha, tfl trudng quay tao thanh ed tde dd goc bang tdn sd gde cua ddng dian. Tfl trudng quay tac dung lan ddng dian cam flng trong cae khung day d rdto cac momen lye lam rdto quay vdi tde dpc nhd hem tde dp quay cua tfl trudng. Chuyen dpng quay cua rdto dupe sfl dung dd lam quay eae may khae.

- Cdng sudt tiau thu eua dpng co dien ba pha bang cdng sudt tiau thu cua ba cupn day d stato cpng lai.

- Hiau sudt tiau thu cua dpng eo dian ba pha bang cong sudt tiau thu cua ba cupn day d stato cpng lai. Hiau suat cua dpng CO dupe xac dinh bang ti sd gifla cdng sudt CO hpe ^ ma dpng ca sinh ra va cdng sudt tiau thu ^ eua dpng co:

H = 4

51

Hoat ddng 5

Cung cd bai hpc va dinh hudng nhiem vu hpc tap tia'p theo

GV yau cdu HS lam cac bai tap trdc nghieni trong phia'u hpc tap dd cung cd kiah thflc

- Lam cae bai tap vd nha 1,2, 3,4 SGK.

- 6n lai kia'n thflc vd sudt dian dpng cam flng, vat liau tfl.

PHlfiU HOC TAP

cau 1. Thi nghiam dupe bd tri nhu hinh ve. Quay

nam cham chfl U quanh true quay vdi van tde

gde COQ . Ket luan nao sau day dung khi ndi vd

sy chuyen dpng dpng eua kim nam cham khi

nam cham chfl U da quay dn dinh ?

A. kim nam cham quay vdi van tde gde co > COQ.

B. kim nam cham quay vdi van tde goc co = COQ.

C. kim nam cham quay vdi van tde gde co <C0Q.

D. kim nam cham diing yan.

c a u 2. Mpt dpng CO dien xoay chidu tiau thu edng suSft l,5kW va cd hifu sudt

80%. Cdng CO hpc do dpng co sinh ra trong 30 phflt la

V s '

A. 2,16.10^L B. 21,6.10^J.

C. 216.10^L D. 0,216.10^J.

Can 3. Bd tri thi nghidm nhu hinh ban, nam cham

chfl U cd thd quay quanh mpt true, khung day

kin dat trong ldng nam cham chfl U va cung

cd thd quay quanh mpt true. Quay nam cham

chfl U sao cho tde dp quay dn dinh vdi vdi

van tde goc co . Ket luan nao sau day dung

khi ndi vd sy quay cua khung day ?

A. Khung day dflng yan.

B. Khung day quay vdi van tde gde co = cOp.

52

C. Khung day quay vdi vdn tde gde co < COQ.

D. Khung day quay vdi van tde gde co > co .

can 4. Phdn cam cua mpt may phat dien xoay chidu mpt pha cd 2 cap eye vd

quay dupe 1200 vdng trong mot phflt. Mdt may phat didn khae ed 5

cap eye cdn phai quay dupe bao nhiau vdng trong mpt giay dd sudt

dian dpng nd gay ra bang may phat didn cd hai cap eye ?

A. 2 vdng. B. 4 vdng.

C. 6 vdng. D. 8 vdng.

Cau 5. Mpt may phat dian ba pha mdc hinh sao cd didn ap pha 127V. Ngudi

ta dua ddng ba pha vao ba dian trd gidng nhau mdc hinh tam giac,

mdi tai cd dien trd 100 Q . Cdng sudt tidu thu cua cac tai la

A. 1452W. B. 1584W.

C. 1684W. D. 1784W.

53

BAI32

MAY BrfN AP. TRUYDN TAI DifiN

I-MUCTlfiU

1. Vi kid'n thflc

- Phat bidu dupe tac dung cua may bia'n ap va trinh bay dupe nguyan tde hoat dpng va ca'u tao cua may bi^n ap. - Nau dupe edng dung va Ipi ich eua may bien ap, sy bien ddi dian ap va cudng dp ddng dien qua may bia'n ap.

- Md ta dupe cau tao cua may bia'n dp.

- Tham gia giai thieh nguyan tde hoat dpng eua may bidn ap.

- Tham gia xay dung cac bidu thflc —^ = —^ ; — = —- • U2 N2 I2 u,

2. Vi kl ndng

- Van dung kien thflc hien tupng cam flng dipn tfl, giai thich nguyen tde hoat dpng cua may bia'n ap.

- Ap dung cae bidu thflc vd suat dien dpng, dinh luat 6m, cdng sudt dd thiet lap cac bidu thflc lien he gifla dien ap va cudng dp ddng dian d cac cupn so cap va thfl cap eua may bie'n ap.

n - C H u i N B I

Giao vien

- May bia'n ap hpc sinh.

- Ddng hd da nang hian sd.

- Ngudn xoay chidu.

- Mdu dien trd cdng sudt.

- Khoa dien.

- Bang lap rap.

- Bp day nd'i mach.

- Bang so dd truydn tai dian nang.

54

Hpc sinh

- 6n lai kia'n thflc vd sudt dien dpng cam ihig, vat liau tfl.

Ill - THifiT Kg HOAT D 6 N G DAY HOC

Hoat ddng ciia hoc sinh

Hoat ddng 1

Kiem tra, chu^n bi dieu kian xudt phat. Dat van de


\'

HS nhan thflc dupe vdn dd cua bai hpc

Hoat ddng 2

Nghien cflu ca'u tao va nguyen

tac hoat dpng ciia may bie'n ap


Trp gitip cua giao vi^n

GV nau cau hdi kiem tra kiaii thflc cu

- Trinh bay cdu tao va nguyan tde hoat dpng eua dpng eo khong ddng bp ba pha?

Dat vdn de : May bien ap la gi ? Vi sao trong ha thdng truydn tai ddng dien xoay chidu di xa khdng thd thia'u may bien ap ? Bai hpc ngay hdm nay giup chflng ta giai dap nhflng cau hdi dd.

GV nau cau hdi vd vdn dd edn nghien

cflu

- Cho mpt thi nghiam dupe bd tri nhu

hinh ve dudi day, hai cupn day cd sd

vdng day Ni,N2 dupe dat vao ldi sdt

chfl U va khep kin blifg loi sdt chfl I.

Na'u dat vao hai ddu cupn day N] mpt

dien ap xoay chidu thi sd chi cua vdn ka

V2 nhu tha' nao? So sanh sd chi eua V2

vaVi?

(~>® N, N, *

55

- Ddng dian xoay chidu trong cupn

day N| tao ra tfl trudng b i ^ ddi

trong ldi sat, do dd tfl thdng qua ldi

sat eung bien ddi theo. Tfl thdng

biah ddi trong ldi sdt xuyan qua

cupn day Nj se sinh ra trong cupn

nay mpt sudt dian dpng cam flng va

tao ra dian ap d hai ddu cupn nay. Vi

vay vdnke Vj cd sd ehi khae khdng.

- Sudt dian dpng ty cam tran

cupn Nl:

C] = -Nl — = -COCPQN] cos cot. dt

Sudt dian dpng cam flng tran

cupn Nj:

62 = -N2 — = -COCP0N2 cos cot dt

E, _ N |

Dodo

€2 N2 E2 N2

Mat khae, hai vdnk^ do sudt dipn

dpng trdn hai cupn day nan sd

chi cua chflng phu thude vdo ti

sd N-


- Cdn ed hai cupn day ed sd vdng

Nt,N2 dupe lap theo so dd tran.

Dian dp xoay chidu mdc vdo cupn day N| Idy tfl bidn thd hpc sinh loai 12 V.

GV ndu cac eau hdi gpi y

- Hian tupng gi xay ra ddi vdi loi sdt

khi dat mpt dian ap xoay chidu vao cupn

day N| ?

- Tfl thdng bian thian trong ldi sdt dupe

truydn qua Nj thi trong cupn ddy Nj

xudt hian hian tupng gi ?

- Sd chi cua hai vdnke ed quan ha nhu

thd nao ddi vdi sudt dian ddng ty cam

tran cupn Ni va sudt dian dpng cam irng

tran cupn Nj ?

- Sua't dien dpng ty cam tran cupn N; va

sudt dian dpng cam iing tran cupn Nj cd

quan he nhu thef nao dd'i vdi sd vdng day

N„N2?

GV ndu cau hdi thia't ka' phuong an thi nghiem

- Hay thidt ka' phuong an thi nghiam dd

kidm tra ?

56

HS quan sat GV tiah hanh thi nghiam va rut ra kai luan

- Vdn kd V2 ed sd chi khae khdng.

E,. U, N,

HS tidp thu, ghi nhd

GV tia'n hanh thi nghiam, yau cdu HS quan sat va rut ra kdt luan.

- Thi nghiam sfl dung hai cupn day cd sd vdng tucmg flng la 1200 vdng, 250 vdng.

GV thdng bao

- Thia't bi ehung ta vfla ldp rap dd lam

thi nghiem d tren gpi la may bia'n ap.

- May bia'n dp la thiet bi hoat dpng dya tran hien tupng cam flng dipn tfl, dung dd bidn ddi dian ap xoay chidu ma khdng lam thay ddi tdn sd cua nd.

- May biah ap gdm hai cudn ddy cd sd vdng qudn tran mpt loi sdt kin. Ldi sdt thudng 1dm bang eac la sdt hoac thep pha silic ghep each dian vdi nhau de giam hao phi dian nang do ddng phu- cd. Cac cupn day thudng lam bang ddng va dat each dian vdi nhau vd each dipn vdi ldi sat.

57

- Mpt trong hai cupn day cua may bien ap dupe ndi vdi ngudn dian xoay chidu, dupe gpi la cupn so cdp. Cupn thfl hai dupe ndi vdi tai tiau thu dupe gpi la cupn thfl cdp.

Hoat ddng 3

Nghien cflu six bie'n ddi dian ap

va cudng dp ddng dien qua may

bien ap


- Na'u bd qua dian trd cua day quan thi cd thd coi dien ap hiau dung d hai ddu mdi cupn day bang sudt dien dpng hiau dung tuong flng trong mdi cupn day. Do dd :

U ^ ^ N ^

U2 N2

- Neu N2 > N, thi U2 > Uj : May cd

tac dung tang dien ap (may tang ap).

- Ndu N2 < Nl thi U2 < Ul : May cd

tac dung giam dipn ap (may ha ap).

GV nau cau hdi vd va'n dd cdn nghian cflu

- Khi mach hd nhu thi nghiam d tran thi sd chi cua cdc vdnka' chinh la dien dp d hai ddu cua mdi cupn day va cung chinh la sudt dian dpng hiau dung d hai ddu mdi cupn day. Ndu ndi mach dien thanh

mach kin thi bidu thflc —^ E2

U ^ ^ N ^

U2 N2

edn dung nfla khdng ? Khi nao thi

may bien ap bia'n ddi dien ap tang?

Khi nao may bien ap bien ddi dian ap

giam ?

GV nau eae cdu hdi gpi f

- Dian dp hai ddu cupn thfl cdp va so

cdp lian he vdi sudt dian dpng va cudng

dp ddng dian trong mach nhu thd nao ?

- Didu kian nao de ca khi mach kin thi

dien ap hai ddu ngudn dien bang sudt

dien dpng cua ngudn dian ?

GV neu cau hdi vd va'n di cdn nghian

cflu tidp

58


- Ne'u coi dien nang hao phi trong niay bien ap la khong dang ke thi cdng suat d hai mach so cdp va thfl cdp la nhu nhau :

^ , = ^ 2 h a y U , I , =U2l2

L U,

- Nhu vay khi may bidn dp lam dien ap tang lan bao nhiau ldn thi cudng dp ddng dian giam di bay nhiau ldn va ngupe lai.


- Sfl dung thi nghiem d tran nhung mach thfl cap cdn phai ndi kin bang mpt tai tiau thu. Do U va I tuong flng d mach thfl cdp vd so cdp bang vdnka' va ampe kd.

HS quan sat GV tidn hanh thi nghiam, Idy sd liau va xfl li sd lieu

HS rut ra ket luan

Na'u coi dien nang hao phi trong

may bia'n dp la khdng dang kd thi

cdng sudt d hai mach so cdp va

thfl cdp la nhu nhau :

- Khi may bien ap bidn ddi dian ap tang hoac giam thi cudng dp ddng dien se bia'n ddi nhu tha' nao ? Tim bidu thflc toan hpe bieu didn sy bia'n ddi dd ?

GV nau eac eau hdi gpi y.

- Na'u coi dien nang hao phi trong may bia'n dp la khdng dang kd thi cdng sudt trong hai mach so cdp va thfl cdp se the nao ?

GV nau cau hdi thidt ke phuong an thi

nghiem

- Hay thia't ke phuong an thi nghiem

kidm tra ?

GV tien hanh thi nghiem, yau cdu HS quan sat, lay sd liau va xfl li sd lipu

59

^ i = ^ 2 h a y U , I , =U2l2

=> I i _ U 2

I2 Uj

Hoat ddng 4 Tim hieu tac dung cua may bie'n ap ddi vdi viec truyen tai dian nang HS thao luan theo nhdm, sau dd dai dian nhdm lan bao cao ka't qua

Cong sudt hao phi tran day Id :

A ^ ^ R I ^

=:>AS^ = R J (U coscp)

Cdch 1 : Giam dian trd R cua dudng day. Day la each lam tdn kem vi phai tang tia't dipn eua day, do dd tdn nhieu kim loai lam day va phai tang sfle chiu dyng cua cae cpt dian. Cdch 2 : Tang dian ap U d noi phat dian va giam dian ap d noi tidu thu dian tdi gia tri cdn thidt. Cach nay cd thd thyc hien dcm gian bang may bien ap, do dd dupe ap dung rpng rai.

Hoat ddng 5 Cung cd bai hpc va djnh hudng nhiem vu hpc tap tiep theo

'

GV nau eau hdi vd vdn dd cdn nghian cihi

- Tai sao khi truydn tai dian nang di xa thi dien nang thudng bi tiau hao dang kd ? Hay tim each khdc phue hian tupng tran ?

GV nau cae cau hdi gpi y - Khi dian nang chay tran day ddn thi dien nang tiau hao do hian tupng gi ? - Cdng sudt hao phi do toa nhiat tran dudng day dupe xae dinh nhu tha' nao ? - Na'u gpi ^ la cdng sudt truydn di, coscp la ha sd cdng sudt cua mach difn thi cdng sudt hao phi dupe xac dinh theo 9^ va coscp nhu tha' nao ?

- Dya vao edng thflc xae dinh A ^ , hay tim each khdc phuc hao phi dipn nang ? - Trong cdc each khdc phuc, each nao da thyc hian va cd tinh kinh ta' cao ?

GV yau cdu HS lam cac bai tap trdc nghiam trong phidu hpc tap dd cung cd kia'n thflc - Lam cac bai tap ve nha 1, 2, 3, 4 SGK. - 6n lai cac kia'n thflc vd ddng dian xoay chidu.

60

PHlfiu HOC TAP

cau 1. May bia'n ap biah ddi dian ap xoay chidu ma khong lam thay ddi

A. bian dp cua dian ap.

B. gia tri hipu dung cua dian dp.

C. bian dp va tdn sd cua dien ap.

D. tdn sd cua dian ap.

Cau 2. Nû tang sd vdng day cua cupn thfl cdp ldn hon sd vdng day eua cupn so cdp thi

A. dian ap tran cudn thfl cdp tang va ldn hon dian ap trdn cupn so cdp.

B. dian ap tran cupn thfl cdp giam va nhd hon dian ap tran cupn so cdp.

C dian ap tran cupn thfl cap tang nhung ludn nhd hon dien ap tren

cupn so cdp.

D. dien dp tran cupn thfl cdp khdng thay ddi.

Cau 3. Cho mpt dien dp xoay chidu vao ddu vao cua mpt may bia'n ap thi dien

ap d ddu ra cd gia tri hieu dung tang gdp hai lan gia tri hieu dung cua

dien ap ddu vao. Cudng dp ddng dien d ddu ra se

A. tang gap hai ldn.

B. giam hai ldn.

C. tang bdn ldn.

D. khdng thay ddi.

c a u 4. Khi cha' tao may tang ap, nan dung day cua cupn thfl cdp la loai day

CO dudng kinh

A. to hon dudng kinh day eua cupn so cdp.

B. nhd hem dudng kinh day cua cupn so cdp.

C. bang dudng kinh day cua cupn so cap.

D. bat kl.

Cau 5. Cach lam nao trong cac each lam sau day lam giam edng sudt hao phi cua he thdng truydn tai dien ?

A. tang dien ap d noi phat dien.

B. giam dien ap d noi phat dien.

C. tang cong sudt truydn di.

D. giam cdng sua't truyen di.

61

cau 6. Ka't luan nao trong cac ket luan sau day sai khi ndi ve cdng sudt hao phi tran dudng day tai dien ? Cdng sudt hao phi

A. ti la vdi chidu dai dudng day tai dien.

B. ti la nghich vdi tie't dian day tai dien.

C. ti la nghich vdi binh phucfng dian ap gifla hai ddu day d tram phat dian.

D. ti la nghich vdi binh phucmg cdng sua't truydn di.

cau 7. Dat mpt dien ap xoay chidu cd gia tri hieu dung 380V vao cupn so cdp cua mdt may tang ap. Tai cupn thfl ca'p, dien ap hiau dung la 12V va cd sd vdng day la 30vdng. Sd vdng day eua cupn so cdp Id

A. 950vdng. B. 850vdng.

C.750vdng. D. 700vdng.

cau 8. Mpt tram phat dian truydn di mpt cdng sudt lOOkW tran day ddn eo dian trd R = 8 Q. Dien ap tfl tram phat dien la U = lOOOV Cdng sudt hao phi tran day ddn la

A. 80kW. B. SOW.

C. 70kW. D. 70W.

62

BAI33

BAI T A P V ^ DONG DifiN XOAY CHlfiu

I-MUCTlfiU

1. Ve kieh thflc

- van dung eac cong thflc dd giai cac bai toan ve doan mach xoay chidu mac ndi tiep.

- Bia't each ve va sfl dung gian dd Fre-nen dd giai eac bai toan vd doan mach xoay chidu mdc ndi tidp.

- Lam quen vdi dang bai tap hpp den.

- Bia't each lam mpt sd bai toan vd truydn tai dian nang di xa va bai toan xac dinh tfl thdng qua khung day.

2. Vi ki nSng

- Ren luyan kT nang van dung cdng thflc de giai cac bai toan vd doan mach xoay chieu mdc nd'i tiep.

- Ren luyen kl nang ve va van dung gian dd Fre - nen.

- Ren luyan ki nang lap luan logic dd lam bai toan vd hop den.

II-CHUXNBI

Giao vien

- Phia'u hpe tap.

Hpc sinh

- On lai cac kia'n thflc va ddng dien xoay chidu.

Ill - THifiT Kfi' HOAT D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chuan b| dieu kien xuat phat

Trp giiip cua giao vien

GV neu cau hdi kiem tra kien thflc cu

- Viet bidu thflc tinh tdng trd eua doan mach R, L, C mdc ndi tie'p ? Ne'u trong doan mach chi cd hai trong ba phdn tfl

63


tran thi tdng trd cua doan mach dupe xac dinh nhu tha' nao ?

- Nau cac da,c didm cua sy bieii ddi dien ap va cudng dp ddng dian qua mdy bien ap ?

- Khi nao doan mach dupe ndi la ed tinh cam khang ? tinh dung khang ?

Hoat ddng 2

Lam bai tap 1 de ren luyen ki nang van dung cac cdng thflc cua doan mach xoay chieu va lam quen vdi bai toan tim eye tri

HS lam bai tap theo nhdm, sau dd dai dian nhdm lan bao cao ka't qua

1. a) Dung khang cua tu dian la :

^ coC

Tdng trd cua doan mach la :

Z^^R?+ z^ «6oa. b) Bieu thflc cua cudng dp ddng dian tfle thdi trong doan mach la:

i = lQCos(l007it + cp)

Trong dd: I o = ^ « 2 A .

Dp leeh pha eua dien ap so vdi

cudng dp ddng dien dupe xac

dinh:

—Z n tancp = —^«-I ,73=:>cpw

R 3

Suy ra, cudng dp ddng dien sdm

pha hon dian dp mpt gde —

GV yau cdu HS lam bai tap 1 trong phia'u hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua.

GV nau eac cau hdi gpi y

- Bidu thflc tdng quat cua cudng dp ddng dien trong mach cd dang nhu thd nao ?

- Trong bidu thflc tdng quat, dai lupng nao cdn xac dinh ?

- Mudn xac dinh gia tri bien dp eiia cudng dp ddng dien ta dp dung dinh luat nao ?

- Xae dinh dp leeh pha bang edng thflc

nao ? Y nghia eua dp lech pha trong

cdng thflc dd ? Suy ra dp lech pha cua

cudng dp ddng dien so vdi dien dp ?

64

Biau thflc cua cudng dp ddng dien la :

i = 2 cos n 100m+ -1 (A) .

2. Cdng sua't tiau thu tran bidn trd

R duoc xac dinh:

o U U'

R

dp dung ba't dang thflc Cd-s i :

( 7} 1 R + ^

R >2Zc

Ddu bang xay rd khi R =

ZQ « 52Q. Khi dd cdng suat dat

gia tri eye dai

2Zr 69W.

- Viet cong thflc tinh cong sudt tiau thu

tran bia'n trd ?

- Cong suat tiau thu tren bia'n trd cd the

tinh theo dien ap va gia tri dien trd nhu

the' nao ?

- Dya vao bieu thflc tinh cdng sudt,

hay cho bidt cdng suat dat gia tri eye

dai khi nao ?

- Cd the ap dung ba't ding thflc Cd si

de tim gia tri eye dai eua edng sudt dupe

khdng ?

Hoat ddng 3

Lam bai tap 2 de k-en luyen kl ve

gian dd vecto Fre - nen cho doan

mach xoay chieu

HS lam bai tap theo nhdm, sau dd

dai dien nhdm lan bao cao kdt qua

a) Cudng dp ddng dien trong mach dupe xac dinh :

I = U R = i l = 0,5A. R 100

u, a m khang: X^=-^ = 100 Q.

GV yau eau HS lam bai tap 2 trong

phia'u hpc tap theo nhdm, sau dd dai

dian nhdm lan bao cao ka't qua.


- Mudn tinh dp ty cam ciia cupn cam va dien dung cua tu dian ta phai tinh dupe dai lupng nao ? Cd the sfl dung dinh luat Om da tinh eac dai lupng dd dupe khdng ?

TKBGVLyi2/2(NC) 65

=>L = - ^ « 0 , 3 1 8 H . CO

Dung khang: Zc = — = 175 Q.

=='C-1

Si 1,82 ^F COZL

b) Tdng trd cua doan mach la ;

Z = J R ^ + | C O L - - ^ V I caC

= 125 Q.

U A B = I Z = 62,5 V.

c) Gian dd Fre - nen nhu hinh ve

U A N = U R + U L

U M B = U L + U C

Tfl gian dd Fre - nen ta thdy

UAN sdm pha hon so vdi UMB

mpt gde SOQ. Vdi:

SOQ = + (p,.

- Mudn sfl dung dinh luat 6m dd tinh cam khang va dung khang cdn phai xac dinh dupe cudng dp ddng dian hiau dung qua hai phdn tfl nay ?

- Hay ve gian dd Fre - nen cho doan

mach ? Chu y cdn phai ve cdc dien ap

theo dflng ti la ?

- Dian ap U ]sj vaUj^g Id dian ap gifla

cac phdn tfl nao? Cdn phai tdng hpp cac

vecto dian ap nao dd cd UAN vdUMB ?

- Quan sat tran gian dd Fre - nen, tfl dd

cho nhan xet vd sy nhanh pha, cham pha

gifla dien dp U^^ vaU^B*?

66

Xet tam giac vudng SOP cd 0P= UOR; SP = UoL,tacd:

tancpi=--^ = l=>cp, = -

vay UAN sdm pha hon so vdi

UMB mpt gde

s5Q = + e p , = ^ . 2 * 4

Cung tfl gian dd Fre - nen :

UAB=V(OP)'+(OQf

= ^ u 2 + ( U c - U L f

= 62,5 (V).

Hoat ddng 4

Lam quen vdi dang bai toan hpp den

HS lam bai tap theo nhdm, sau dd dai dian nhdm ldn bao cao ket qua

Tacd: i = 0,5sin| l007rt + ~

i=0,5cos 'lOOnt+^-^' 6 2

71 = 0,5cos lOOnt— |{A)

GV yau cdu HS lam bai tap 3 trong phia'u hpc tap theo nhdm, sau dd dai dian nhdm lan bao cao kdt qua.


- Lieu rang doan mach cd the chfla hai phdn tfl la cudn cam va tu dien dupe khdng ?

- Na'u doan mach cupn cam va tu dian thi dp lach pha cua cudng dp ddng dien so vdi dien ap hai ddu doan mach bang bao nhiau ?

- Hay xac dinh dp lech pha gifla dien ap va cudng dp ddng dian. Tfl dd hay cho bie't doan mach cd tinh cam khang hay dung khang ?

67

Tfl bidu thflc eua u va i ta thay dian ap sdm pha hon cudng dp ddng

dien mpt gde — • Doan mach cd

tmh cam khang nan gdm cupn cam

thudn va dien trd mdc ndi tia'p.

Mat khae, ta cd

Z = ^R^ + Z[ = —= 120Q R

tan (0 = —^ = V3 R

Giai he phuong trinh: R = 60Q,

Z L = 6 0 A ^ = « 1 0 4 Q

b) Cdng sudt tiau thu cua doan mach la :

9^ = UIcoscp = 7,5W.

Hoat ddng 5

Lam bai tap 4 de ren luyen each tinh tfl thdng qua mot dien tich


Ap dung cdng thflc : 0^ = BSeosa

- Tai thdi diem ban ddu t = O phap

tuya'n eua khung day ed hudng

vdi vecto cam img tfl nan a = O.

- Tai thdi didm t, a = 27cft nan tfl

thong qua mdt vdng day tai thdi

diem t dupe xae dinh :

cpj = BSeos27ift

^ O i =2.10'^cos207it (Wb).

- Tdng trd eua doan mach dupe xac

dinh nhu tha' nao ?

- Dp lech pha cua dien ap so vdi cudng dp ddng dian duoc xac dinh nhu the nao ?

GV yau cdu HS lam bai tap 4 trong phia'u hpc tap theo nhdm, sau dd dai dian nhdm lan bao cao ka't qua.

- Bidu thflc tfl thong qua mdi vdng day

cd dang nhu the nao ?

- Xac dinh gde a tai thdi didm t ?

68

Sudt dien dpng cam flng tfle thdi trong khung day :

dO, e = - N ^- = NBS2;rsin27ift

dt

zê = 6,28sin20Kt (V).

Sudt dien dpng hieu dung la :

E = ^ . 4 , 4 V .

Vi dian trd trong cua khung day

khdng dang kd nan sudt dien dpng

bang dien ap dat vao hai ddu dien

trd. Suy ra:

Cudng dp ddng dien hieu dung

E chay qua dien trd: I = — « 0,11 A.

Hoat ddng 6

Lam quen vdi bai toan truyen tai dien ndng di xa

HS lam bai tap theo nhdm, sau dd

dai dian nhdm lan bao cao ke't qua

Tacd: A9^ = Rl^

Trong dd dien trd va cudng dp

ddng dien dupe xac dinh :

R = p '=2 ,5 .10 -^ ^•^•^^' - 3 Q . S 0,5.10-'

I = = lOOA. U cos cp

Cdng sua't hao phi tran day :

A ^ = RI^=30W.

- Dian ap dat vao hai ddu R dupe xac

dinh nhu the nao ?

- Neu coi dien trd cua khung day la khdng dang kd, khi ndi vdi dian trd R tao thanh mach kin thi suat dian dpng ty cam va dien dp dat vao R cd dac diem gi ?

GV yau cdu HS lam bai tap 5 trong phia'u hoc tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua.

- Cdng sudt hao phi tran dudng day dupe xac dinh nhu the nao ?

- Mudn xac dinh dixgc cong sua't hao phi can phai xac dinh dupe nhflng dai lupng nao ?

- Dien trd tran dudng day dupe xac dinh bang cdng thflc nao ?

- Khi truydn tai dian cdn cd bao nhiau day din ? Mdi day ddn cd chidu dai bang bao nhiau ?

- Hieu sudt truydn tai dian dupe xae dinh bang cdng thflc nao ?

69

Hiau sudt truydn tai dien la :

x\ = W «94,4%.

PHlfiu HOC T A P

cau 1. Doan mach AB nhu hinh ve

R

B

gdm mpt bien trd va mpt tu dian cd didn dung C = 6l,3|iF mdc ndi tidp.

Dat vao hai ddu A, B mpt dien dp xoay chidu u = 120eosl007tt(V).

1. Didu chinh eho dien trd cua bien trd R, = 30Q.

a) Tinh tdng trd cua toan mach.

b) Via't bieu thflc eua cudng dp ddng dien tfle thdi trong doan mach.

2. Cdn didu ehinh cho dien trd cua bia'n trd den gia tri nao dd cdng sudt tran bidn trd dat eye dai ? Tinh gia tri eye dai dd.

cau 2. Mdt doan mach dian AB nhu hinh ve

R

-nmm^ B A M N

gdm mpt dien trd thudn R = 100 Q, mpt cupn cam thudn va mpt tu dien mac nd'i tiep. Bie't dian ap hieu dung gifla hai ddu dian trd, cupn cam, tu dien ldn lupt la UR = 50V ;UL = 50V ;Uc = 87,5V ; tdn sd ddng dian la 50Hz. .

a) Tinh dd ty cam cua cupn cam va dien dung cua tu dian.

b) Tinh tdng trd eua doan mach AB va dipn ap hiau dung U^B-

c) Ve gian dd Fre - nen. Can cfl vao gian dd dd: tim dp lach pha ciia dien dp gifla hai diem A va N so vdi dipn ap giua hai diem M va B;

tim lai U^B-

70

cau 3. Mpt doan mach chfla hai trong ba phdn tfl: tu dian, dian trd thudn, cupn cam thudn mdc ndi tidp. Bia't dien ap gifla gifla hai ddu doan mach va cudng dp ddng dipn qua nd ldn lupt cd bieu thflc:

u = 60cosl00m(V)va i = 0,5sin I007lt+- (A). 6.

a) Hdi trong doan mach cd cac phdn tfl nao ? Tinh dung khdng, cam khang hoac dian trd tuong flng vdi mdi phdn tfl dd.

b) Tinh cdng sudt tiau thu cua doan mach.

cau 4. Mpt khung ddy ddn phang gdm 50 vdng day, mdi vdng cd dipn tich 400 cm^ dat trong tfl trudng deu ed cam flng tfl bang 0,05T. Luc t = 0 phap tuyen eua khung day cd hudng vdi vecto cam flng tfl. Cho khung day quay vdi tde dp khdng ddi 600 vdng/phut. True quay cua khung vudng gde vdi cac dudng sflc tfl.

a) Vidt bidu thflc cua tfl thdng qua mdi vong day theo thdi gian.

b) Lap bidu thflc eua sudt dien dpng cam flng tfle thdi trong kh"ung day. Ldy 7t = 3,14.

e) Ndi hai ddu khung day vdi dian trd thudn R =40Q. Dien trd khung day khdng dang ke. Tinh cudng dp ddng dian hieu dung cua ddng dien qua dien trd.

cau 5. Mpt dudng day tai dien xoay chidu mpt pha den noi tiau thii ^ xa 3 km.

Gia thia't day ddn lam bang nhdm cd dien trd suat p = 2,5.10 Q.mva cd

tiet dien bang 0,5cm^ Dien ap va edng sudt truyen di d tram phat dien ldn

lupt la U = 6 kV, ^ = 540kW. Hp sd cdng sudt cua mach dien cos cp = 0,9.

Tinh edng sudt hao phi tran dudng day va hifu sudt truyen tai dien.

71

BAI34

Thuc hanh : KHAO S A T DOAN MACH XOAY CHlfiu

CO R, L, C MAC N 6 I TifiP

I - M U C T l £ U

1, Vi kien thiic

- Biet each khao sat mach dian xoay chidu RLC mdc nd'i tia'p bang thyc nghiem de hidu y nghia thyc ta' cua nhflng dai lupng co ban la trd khang, sy lech pha, hian tupng cpng hudng dien.

- Dung dupe dao dpng ki dien tfl, may phat am tdn va cac dung cu do thdng thudng de lam thyc nghiem, lian he gifla cac phep do cu the vdi viec ve gian dd vecto.

- Bang thyc nghiam cung cd kidn thflc vd dao dpng dian tfl, cung ed kia'n thflc vd cpng hudng trong dao dpng dien vdi dao dpng co.

2. Ve ki nang

- Ren luyen ki nang phan tich lya chpn phuong an thi nghiam.

- Ren luyan ki nang mdc so dd mach dian, sfl dung cac dung cu do nhu vdnkd, ampe ke...

- Ren luyan ki nang sfl dung dao dpng ki dian tfl trong thyc nghiam.

- Ren luyen ki nang xfl li thdng tin thu dupe khi tien haiih thi nghiem.

- Ren luyan ki nang phdi hpp hanh dpng trong nhdm.

II-CHUXNBI

Giao vien

- Chudn bi mpt bien trd, mpt tu dien cd 20|^F, mpt cupn day cd dp ty cam 0,5H,

mpt may phat am tdn, mpt dao dpng ki dien tfl hai chum tia, mpt bien thd HS.

- Chudn bi 4 bd thi nghiem gdm: tu dipn ed lOîF, cupn cam 0,5H cd didn trd

thudn cd 20 Q , ampe ka' xoay chidu, vdnke xoay chidu, bia'n tha' HS, ngdt dien.

- Ve hinh 34.3 va 34.4 SGK tren giay khd AQ.

- Ve niach dian khao sat dao dpng dien RLC ndi tia'p tran gidy khd AQ.

72

Hpc sinh

- 6n lai eae kien thflc vd ddng dipn xoay chidu.

- Chudn bi gidy ve dd thi.

m - THifiT K£' HOAT DONG DAY HOC


Hoat ddng 1

Kiem tra, chuan bi dieu kien xuat phat


Hoat ddng 2.

Thiet ka' cac phuong an thi nghiem khao sat mach dien xoay chieu bang dao dpng ki dien tfl

HS thao luan theo nhdm, sau dd dai dien nhdm lan bao cao ket qua

- HS ve mach dian chi ed tu dian, chi ed cupn cam va doan mach RLC ndi tia'p trong dd cd sfl dung dao dpng ki dipn tfl va may phat am tdn. Giai thieh nguyan tde boat dpng cua mach khi tien hanh thi nghiem.


GV nau cdu hdi kiem tra kia'n thflc cu

~ Viet edng thflc xae dinh : cam khang, dung khang, tdng trd eua doan mach xoay chidu RLC ndi tiep, dp lech pha gifla dien ap va cudng dp ddng dien trong mach RLC ?

- Nau ddu kien dd xay ra hien tupng cpng hudng dian trong mach RLC ndi tiep ?

- Nhan xet gi vd sy lach pha gifla cucmg dp ddng dian va dien ap cua doan mach chi cd tu dian, chi ed cupn cam thudn ?

GV nau cau hdi thia't ke phuong an thi nghiem

- Hay thia't ka' phuong an thi nghiem kiem tra dp lech pha gifla dien ap so vdi cudng dp ddng dian eua doan mach chi ed tu dien, ehi cd cupn cam va doan mach RLC ndi tiep ?

GV nau cau hdi gpi y

- Chung ta da sfl dung dao dpng ki dien tfl dd tia'n hanh thi nghiem d cac bai trudc. Lieu rdng cd thd tidp tuc sfl dung dao dpng ki dien tfl dd tie'n hanh thi nghiam d bai nay dupe khong ?

73

- Na'u HS khdng ve dupe, GV yau cdu va gpi y de HS giai thich nguyen tde hoat dpng cua mach dien hinh 34.3 va 34.4 SGK.

- Giai thich nguyan tac hoat dpng

cua mach dien RLC ndi tiep khi

tia'n hanh thi nghiem {mach dien

ndy duac GV vetren gidy kho AQ)

HS lam viae ca nhan

- Hay ve so dd mach dian ed sfl dung dao dpng ki dian tfl di nghian cflu dp lach pha gifla dian dp va cudng dp ddng dian ddi vdi cac doan mach ndi tran ?

- Vi dao dpng ki didn tfl khdng do true tia'p ddng dien nan thay vi nghian cflu ddng dian ngudi ta nghian cflu dai lupng nao ? Dai lupng dd dupe ldy is ddu tran mach dien ?

- Hay giai thieh nguyan tde boat dpng

cua cac so do mach dipn hinh 34.3 va

34.4?

GV tia'n hanh thi nghiem theo cac budc

trong bai thyc hanh, yau cdu HS quan

sat va ve dd thi vao gia'y. Tfl do, suy ra

gia tri bian dp va cac dp lech pha trong

eac doan mach da quan sat.

Lm y : Ddi vdi budc 5 cua phuang dn

thi nghiem I, de quan sdt dong thdi do

thi cua hai dao dpng lech pha do R, L,

C thi nen ddi hai vi tri idy tin hieu tren

R cho nhau. Khi do vi tri ndi dat cOa cd

hai cdng Yj va Y2 d ddu mach, tin hieu

d cong Yj (tin hieu lay tren R) nhU la

tin hieu ddng dien, tin hieu d cong Y2 Id

dien dp cua cd mach RLC.

Hoat ddng 3 .

Thie't ke cac phuong an thi

nghiem khao sat mach dian xoay

chieu RLC ndi tiep bang vdnke'

va ampe ke'

GV neu cau hdi dd HS thidt ke phuong an thi nghiem dung vdnke va ampe k^

- Khi dung dao dpng ki dien tu de nghi&J

cflu doan mach RLC ndi tiep ta mdi dflng

74

HS thao luan theo nhdm, sau dd dai dien nhdm lan bao cao ket qua

- Ta sfl dung ampe ke mdc ndi tia'p vdi mach RLC de do cudng dp ddng dien hieu dung qua mach. Dung vdnke do dien ap hieu dung tran mdi phdn tfl. Can cfl vao bang sd liau ta ed thd tinh dupe :

L J ' C J ' J

Hoat ddng 4 .

Phan nhdm, tien hanh thi

nghiem

Cac nhdm trudng lan nhan thidt bi thi nghiem vd cho nhdm va nhan mdu bao cao thi nghiem.

- Sau khi cae nhdm da tidn hanh xong ea hai phuong an thi nghiem thi lau chui, xep lai gpn gang cae dung cu thi nghiam va ban giao lai cac thia't bi thi nghiem cho GV.

Hoat dong 5.

Xijr li sd lieu va via't bao cao thi

nghiam

HS thao luan nhdm, sau dd ca nhan xfl li sd lieu va viet bao cao.

lai d viec nghian cflu dinh tinh, chua

cho phep ta xac dinh gia tri cua

Z L . Z^va Z toan mach. Hay thidt kd

mpt phuong an thi nghiem khae cho phep ta xac dinh mpt cac dinh lupng cac gia tri tran ?


- Mudn xac dinh cac gia tri tran ta phai

xac dinh nhiing dai lupng nao?

- Cd thd su dung dinh luat 6 m de xac

dinh Z L , Z(-va Z toan mach dupe

khdng ? Na'u dupe, ta phai do nhiing gia tri nao ? Sfl dung dung cu do nao ?

GV chia ldp thanh cac nhdm thi

nghiam.

- Trong qua trinh HS lam thi nghiam,

GV di tdi tflng ban thi nghiem dd dinh

hudng giup dd HS khi HS gap khd

khan.

Yau cdu HS xfl li sd lieu va via't bao

cao thi nghiem theo mdu cd sin trong

SGK.

GV thu bao cao thi nghiem cua HS sau khi HS da xfl li sd lieu va via't xong

bao cao thi nghiem.

75

CHWONG VL SONG ANH SANG

BAI35

TAN SAC ANH SANG

I-MUCTl£U

1. Ve kie'n thflc

- Nam dupe hien tupng tan sdc anh sang va giai thich dupe hien tupng.

- Dua ra dupe gia thuya't I dd giai thich hian tupng tan sdc anh sang va suy luan ra dupe he qua cua cac gia thuya't dd kidm tra dupe bang thyc nghiem.

- Dd xudt dupe cae phuong an thi nghiam kidm tra ha qua.

- Nam viing khai niam anh sang trdng, anh sang dcfn sdc.

2. Ve ki nang

- Ren luyen ki nang dua ra dy doan, suy luan he qua logic eua dy doan.

- Ren luyen ki nang thidt kd phucftig an thi nghiem kidm tra.

- Ren luyen ki nang quan sat, rut ra ke't luan.

- Ren luyen ki nang giai thich cae hien tupng vat li.

II-CHUXNBI

Giao vien

- Chudn bi bp thi nghiem chflng minh hien tupng tan sac anh sang.

Hpc sinh

- On lai cac kian thflc va lang kinh.

- 6n lai cac kien thflc vd anh sang trang, anh sang mau, sy phan tich anh sang trdng, sy trdn cac anh sang mau da hpc d ldp 9 THCS.

76

m - THlfiT Kg HOAT D 6 N G DAY HOC

Hoat ddng cua hpc sinh Trd giiip cua giao vien

Hoat ddng 1

Kiem tra, chu^n bi dieu kien xua't phat. Dat va'n de


HS nhan thflc dupe vdn dd eua bai hoc

GV neu cau hdi kiem tra kia'n thflc cii

- Nau cac ngudn phat ra anh sang trdng ma cac em da hpc d ldp 9 THCS.

- Nau dac didm eua tia sang di qua lang kinh.

Dat vdn de : Trong nhung ngay he, khi con mua vfla tanh, tran bdu trdi ddi khi xudt hian eac vdng nhieu mau sdc vdt ngang vdm trdi. Ngudi ta thudng gpi la cdu vdng. Tai sao cd hien tupng nhu vdy? Bai hpc ngay hdm nay giup chflng ta tra ldi cau hdi dd.

Hoat ddng 2

Nghien cihi hien tupng tan sac anh sang


- Chidu anh sang mat trdi hoac anh sang cua mpt den spi dot qua mot lang kinh. - Mat HS lan bd tri thi nghiem vdi cac thiet bi cd sdn

HS quan sat GV tien hanh thi nghiam va rut ra ke't luan

- Ka't qua thu dupe va't sang Id quan sat tren bang khdng nhirng bi lech vd phia day cua ldng kinh so vdi tia tdi ma cdn bi taeh thanh nhidu mau. Tren man hflng thu dupe mpt dai sang nhidu mau sdc.

GV nau cau hdi vd vdn de cdn nghian cflu

- Lam the nao de tao dai sang mau nhu d eau vdng trong phdng thi nghiem ? GV yeu eau HS bd tri thi nghiem

- Chiing ta cd cae thiet bi thi nghiam nhu tran ban, em nao cd thd lan bd tri thi nghiem ?

GV tia'n hanh thi nghiem, yau cdu HS quan sat va rut ra ket luan

77


HS thao luan ehung toan ldp ~ Suy nghl, trao ddi, dya vao kinh nghiem ciia cudc sdng... dua ra dy doan: anh sang trdng gdm nhidu anh sang cd mau sdc khae nhau, eac mau nay Ipch khae nhau khi di qua lang kinh...

HS thao luan nhdm

- Ha qua ciia gia thuya't 1 : Ne'u lang kinh nhudm mau cho anh sang thi anh sang cd mau ba't ki khi di qua lang kinh thi cung bi tach thanh nhidu mau.

GV thdng bao - Hien tupng thu dupe trong thi nghiam nay gpi la hian tupng tan sac anh sang. - Dai mau sdc thu dupe gpi la quang phd anh sang do den phat ra.

GV nau cau hdi vd vdn dd cdn nghian cflu tia'p

- Tai sao anh sang trdng khi di qua lang kinh thi bi tach thanh nhidu mau ?

GV kd chuyan lieh sfl de dua tham dy doan : Khi mdi nghian cflu hien tucfng tan sdc anh sang thi Niuton cd ldi giai thieh rang lang kinh da nhupm eac mau eho anh sang. vay, ehung ta cd hai gia thuydt: Gid thuyet I : iSng kinh da "nhupm" cac mau cho anh sang. Gid thuyet 2 : anh sang trdng gdm nhidu anh sang cd mau sdc khae nhau, cac mau nay lech khae nhau khi di qua lang kinh.

GV yau cdu HS thao luan dd suy ra ha qua eua gia thuydt I cd thd kidm tra dupctrdng thi nghiam GV nau cau hdi gpi y

- Na'u gia thuydt 1 la dung thi anh sang cd mpt mau di qua lang kinh se tha'nao ?

78

HS thao luan nhdm

- Dung anh sang lase, dung anh sang qua kinh loc mau... sau dd chia'u qua lang kinh.

- Trao ddi, suy nghi : Dung mpt khe nhd tach la'y mpt mau ndo dd, cho anh sang cd mdu dd qua lang kinh, sau lang kinh dd dat man dd hflng anh sang nay xem cd bi tach thanh nhidu mau hay khdng.

HS quan sat GV tidn hanh thi nghiam va rut ra ka't' ludn

- Ket qua thdy anh sang khdng bi tdeh thanh nhidu mdu. Vdy gia thuydt 1 la khdng ehinh xae.


HS thao luan theo nhdm - Na'u trdn cac anh sang don sdc cd mau khae nhau thi se phai dupe anh sang trdng.

GV nau eau hdi thidt ke phucmg an thi nghiam kiem tra

- Hay thia't ka' phuong an thi nghiam dd kidm tra ha qua cua gia thuya't 1 ?

GV tia'n hanh thi nghiam, yau cdu HS quan sat va rut ra ket luan

GV thdng bao vd bd sung gia thuya't 2 - Dinh nghia anh sang dcfn sdc: anh sang don sdc la anh sang khdng bi tan sdc ma chi bi lach khi di qua lang kinh. - Bd sung gia thuydt 2 : Nhu vay, vdi dinh nghia anh sang don sac nay cd thd bd sung gia thuyet 2 la: anh sang trdng gdm nhidu dnh sang don sdc, va lang kinh cd chia't sudt khae nhau vdi cac anh sang don sdc cd mau khae nhau. GV yeu cdu HS thao luan dd suy ludn mdt ha qua cua gia thuyet 2 cd thd kidm tra bang thyc nghiam

GV nau cau hdi thia't ka' phuong an thi nghiam kidm tra

79

HS thao luan theo nhdm

- Dung tha'u kinh hoac guong cdu dd bpi tu cae anh sang don sac Id ra trong thi nghiem TSAS

- Dung mpt sd anh sang mau khae nhau trdn vao nhau de tdng hpp...

HS chu y quan sat va rut ra ket

luan

- Len bd tri thi nghiam, dat lang kinh thfl 2 ngupe chidu, hflng cac anh sang da tan sdc. Ket qua thu dupe mpt ddi sang trdng sau lang kinh thfl 2

- Nhu vay cae anh sang don sdc sau khi vao lang kinh thfl 2 da tron vao nhau va Id ra khdi lang kinh thanh anh sang trdng. Ka't qua nay khang dinh gia thuya't 2 la dung.

- Hay thia't ke phuong an thi nghiam kiem tra he qua cua gia thuydt 2.

GV nau cac cau hoi gpi y

- Lang kinh da tach anh sang trdng thanh anh sang don sdc liau ed thd tdng hpp lai anh sang trdng bang lang kinh hay khong ?

- vay edn phai dat lang kinh dd nhu tha' nao ?

GV cho mpt HS lan bd tri thi nghiam va tie'n hanh thi nghiam, yau cdu ca 1 ^ chii y quan sat va rut ra kdt luan

GV thdng bao cae flng dung sy tan sac anh sang

80

- Hian tupng tan sac anh sang dupe img dung trong may quang phd de phan tich mpt chum sang da sdc, do cac vat phat ra, thanh cac thanh phdn don sdc. - Nhidu hien tupng quang hpc trong khi quydn xay ra do sy tan sdc anh sang. Dd la vi trudc khi tdi mat ta, cac tia sang mat trdi da bi khuc xa va phan xa trong cac gipt nude.

Hoat ddng 3 Ciing cd bai hpc va dinh hudng nhiem vii hpc tap tie'p theo

HS thao luan theo nhdm

- Khi quay dia cham, thi cac mau lap loe, khi quay nhanh thi cd hian tupng luu anh trong vong mac nan cae mau se tron ddu vao nhau trong mat, va mdt se thu dupe anh sang trdng.

HS quan sat GV tia'n hanh thi nghiam

GV nau cau hdi eung cd kidn thflc - Dan gidy mau lan mpt dia trdn nhu hinh ve 35.3 SGK, cho dia quay vdi tde dp nhat djnh ta se nhin thay mau trdng. Hay giai thich hian tupng quan sat dupe ?

GV gpi y - Na'u bay gid quay dia cham thi se ed hien tupng gi ? va khi quay dia nhanh se ed hien tupng gi ?

GV tie'n hanh thi nghiam dd HS quan sat. - 6n lai cac kie'n thflc vd hien tupng giao thoa va hien tupng nhidu xa sdng nudc. - Lam cac bai tap 1, 2 SGK.

TKBGVLyi2/2(NC) 81

BAI36

NHifiu XA ANH SANG. GIAO THOA ANH SANG

I -MUCTl£u

l.ve'ki^n thiic

- Nam dupe hian tupng nhidu xa anh sang. Bia't dupe mdi dnh sang don sdc cd m6t budc sdng nhdt dinh trong chan khdng. - Di xudt so bp dupe phucmg an thi nghipm quan sat hipn tupng giao thao anh sang. Dua ra dupe dy doan ve hinh anh giao thoa. - Trinh bay dupe thi nghiam l-ang vd hian tupng giao thao anh sang va nau dupe didu kian de xay ra hian tupng giao thoa anh sang. - Tra ldi dupe cau hdi: Tai sao ndi anh sang cd tinh chdt sdng.

2.V€kin5ng

- Ren luyan kl nang thiet ka'phuong an thi nghipm.

- Ren luyan kl nang quan sat thi nghipm.

- Ren luypn kl nang giai thich cac hipn tupng vdt Ii.

H-CHUXNBI

Giao vien

- Oiudn hi thi nghiem giao thoa anh sang.

- Ve hinh 36. i, 36.2, 36.3, 36.4 SGK tran gia'y khd AQ.

Hpc sinh

- On lai cae kien thflc va hipn tuong giao thoa va hipn tupng nhidu xa sdng nude.

m - THlfiT Kfi' HOAT D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chuan bi dieu kian xuat phat Dat van de

Trp giup cua giao vi#n

GV nau cau hdi kidm tra kien thflc cu - Md ta thi nghipm ve hien tupng nhieu xa ciia sdng nudc.

82

HS suy nghl ca nhan tim cau tra ldi - Hien tupng giao thoa sdng nudc. - Neu hai hien tupng dac tnmg eua sdng. Dat vdn de : Khi nhin anh sang Mat Trdi phan xa tran mang nudc xa phdng hay tran vang ddu, ta thay ed eac van mau sac sd. Tai sao cd hian tucmg nhu vay ? Bai hpc ngay hdm nay giup chflng ta suy nghl didu dd.

Hoat ddng 2 •> '

Tim hieu hien tupng nhiau xa

HS thao luan theo nhdm, sau dd dai dien nhdm ldn bao cao ket qua

- Theo nguyan li tmydn thdng cua anh sang thi mat phai dat trong vung ab thi mdt cua ngudi quan sat mdi nhan dupe anh sang chidu tfl Id 0 tdi va mdi trdng thdy Id trdn O.

HS thao luan ehung toan ldp - Dieu nay chflng td da cd mpt sd tia sang tfl O da lech khdi phuong tmydn thang ciia anh sang truydn tdi mat ngudi quan sat. Ld trdn O tya nhu mot ngudn sang.

GV nau cau hdi dd HS tim hieu hien tucmg

- Dung den S chieu sang mpt Id trdn nhd O, khoet d cfla mpt can phdng ldn rat kin. Hdi ngudi quan sat phai dat mat d vi tri nao tran vach V cua phdng ddi dien vdi Id O thi thay Id O ?

GV thdng bao - Thyc te' eho tha'y : Khi dat mdt d didm M chech vdi dudng truyen thang eua mpi tia sang, va sau vai phut de mdt thich nghi dan vdi, bong tdi, ta trdng tha'y rdt rd Id O. GV tia'p tuc nau cac cau hdi de HS tim hidu hian tupng - Ka't qua cua thi nghiem tran eho ehung ta ket luan gi ?

83

HS chu y lang nghe va quan sat hinh ve 36.2 SGK.

Hien tupng thu dupe gidng nhu hien tupng nhidu xa cua sdng nudc.


- Thue nghiem chflng td rdng, khi thu nhd Id trdn tdi mpt mflc nao dd, thi tran vach V khdng cdn cd vdt sang nhu trudc md xudt hian mpt sd va't sang trdn dupe bao quanh bdi cae vanh trdn sang tdi nam xen ke nhau (trong ea vung ab va ngoai vung ab). - Hien tupng nay gidng hien tupng nao cua sdng nudc.

GV thdng bao hien tupng nhidu xa anh sang.

- Hien tupng thu dupe d thi nghiem tran gpi ia hien tupng nhidu xa anh sang.

- Hien tupng nhidu xa anh sang la hian tucmg sanh sang khdng luan theo dinh luat truyen thang, quan sat dupe khi anh sang truydn qua 16 nhd hoac gdn mep nhflng vat trong sudt hoac khOng, trong sudt.

- Dd giai thieh hipn tupng nhidu xa anh sang, Huy-ghen va Fre-nen da khang dinh anh sang cd tinh chat sdng. Id nho hoac khe nhd dupe chia'u sang ed vai tro nhu mpt ngudn phat sdng anh sang. Mdi chum sang don sdc la mpt chiim sang ed budc sdng va tan sd xac dinh.

Trong chan khong, budc sdng cua anh sang don sdc dupe tinh theo cdng;

thflc X, = - , f la tdn sd anh sang.

Trong moi trudng cd chie't sudt n, budc sdng cua anh sang don sdc la

_ V _ c _ A,

Hoat ddng 3

Tim hidu hien tupng giao thoa dnh sang

HS thao luanchung toan ldp

- Cdn phai cd hai ngudn sang la hai nguda kdt hpp. Khi hian tupng giao thoa xay ra se cd nhflng ehd anh sang tang cudng ldn nhau, ed nhflng ehd anh sang triat tiau Idn nhau.

HS chu y ldng nghe va quan sat hinh ve

GV ndu cau hdi vd v^n dd edn nghian cflu

- Na'u anh sang cd tinh chdt sdng thi cd thd xay ra hian tucmg giao thoa dupe. Hay thie't kd phuong an thyc nghiam dd tao ra hien tupng giao thoa anh sang ?


- Gidng nhu sdng nudc, de tao ra dupe hien tupng giao thoa cdn phai cd cac ngudn sang nhu tha' nao ?

- Trong giao thoa sdng nudc, cd nhiJng didm dao dpng vdi bian dp eye dai va nhihig diem dao dpng vdi bian dp eye tidu. Na'u anh sang giao thoa thi cd hinh anh nhu the nao ?

- Lieu cd thd dung mdt ngudn sang chia'u vao hai khe hep dd tao ra hai ngudn sang la hai ngudn ke't hpp dupe khdnig ?

GV md ta thi nghiam cua I-dng vd giao thoa anh sang tran hinh ve 36.3 a SGK

- D la ngudn phat anh sang trdng; F la kinh Ipc sac dung de tach ra chum sang don sdc chieu vao khe hep S rach tran man chdn Mj ; Sj, S2 la hai khe hep, nam rat gdn nhau, song song vdi S, rach tran man chdn M2; M la man quan sat. Toan bp he thdng dupe dat trong mpt dug nhya cd son den trong long dug dd tranh hien tupng phan xa anh sang trong ldng dng.

GV cho mpt sd HS len quan sat hinh anh giao thoa anh sang va md ta hinh anh da quan sat dupe

85

HS quan sat va md ta hinh anh quan sal

- Hinh anh quan sal dupe la nhflng vach sang tdi xen ke nhau.

HS thao luan ehung loan ldp

- Anh sang tfl den D qua kinh Ipc

sac F chia'u vao khe S lam cho khe

S trd thanh ngudn phat sdng anh

sang, truydn ddn hai khe S^, ^.

Hai khe S,, S2 dupe chia'u bdi cung

mdt ngudn sang S, nan trd thanh

hai ngudn ke't hpp cd eung tdn sd.

Hai sdng do S|, S2 dupe chia'u sang

bdi eung mpt ngudn sang S nan trd

thanh hai ngudn kdt hpp cd cung

tan sd. Hai sdng do Sj, S2 phat ra la hai sdng ke't hop. Tai vung khong gian hai sdng dd chdng lan nhau xay ra hien tupng giao thoa.

f^^^^^^^Mi^

GV yau cdu HS giai thich hien tupng

GV thd ehd hoa kien thflc

- Vay hien tUpng giao thoa anh sang la mpt bang chflng thyc nghiem quan trong khang dinh anh sang cd tinh chat sdng.

- Didu kian xay ra hien tupng giao thoa la hai chum sang giao nhau phai la hai chiim sang kdt hpp.

86

- Cac vach sang tdi xen ke nhau quan sdt dupe khi cac sdng giao thoa gpi la eac van giao thoa.

Hoat ddng 4


HS thao luan ehung toan Idp dua ra dy doan

HS ehd y lang nghe.

GV nau cau hdi cung ed bai hpe

- Neu khong dung kinh Ipc sdc F trong thi nghiam I-ang a tren thi hinh anh thu dupe nhu tha' ndo ?

GV cho mpt sd HS lan quan sat hinh anh giao thoa vdi anh sang trdng va mo ta hinh anh giao thoa quan sat dupe.

- HS vd nha lam cac bai tap 1, 2 SGK,

- 6n tap cdc kien thflc vd giao thoa sdng nude va giao thoa sdng anh sang.

87

BAI37

KHOANG VAN. BirdC SONG vA MAu SAC A N H SANG ,'

I - MUC Tl£U

1. va' kie'n thflc

- Nam dupe didu kian dd cd vdn sang, didu kian dd cd van ldi.

- Bia't each xac dinh vi tri van sang, vi tri van tdi va van dung cong thflc xac dinh vi tri van sang va vi tri van tdi dd.

- Bie't each suy ra cdng thflc xac dinh khoang van va van dung edng thflc xac dinh khoang van.

- Thiet ke dupe phucmg an thi nghiam do budc sdng anh sang.

- Bia't dupe khoang dp ldn cua cac anh sang don sdc nhin thdy.

- Bie't dupe mdi lien quan gifla budc sdng anh sang va mau sdc anh sang.

- Bia't dupe mdi lian he gifla chiet sudt va budc sdng anh sang.

2. Vi kl nSng '

- Ren luyen ki nang logic toan hpc dd tim cac edng thflc vd vi tri van sang, vdn tdi, khoang van.

- Ren luyan ki nang dd xua't phuong an thi nghiam.

- Ren luyen ki nang giai thich cae hien tupng vat li.

II-CHUXNBI

Giao vien

- Ve hinh 37.1 SGK tren giay khd AQ.

- Phia'u hpc tap.

Hpc sinh

- On tap cac kia'n thflc ve giao thoa sdng nudc va giao thoa song anh sang.

88

Ill - THifiT Kg HOAT D O N G DAY HOC

Hoat ddng cua hpc sinh Trp giup cua giao vien

Hoat ddng 1

Kiem tra, chuan bi dieu kien xua't phat

GV nau cau hdi kidm tra kien thflc cu - Trong hian tupng giao thoa sdng nudc, nhflng didm ed hiau dudng di thoa man didu kian gi thi dao dpng vdi bian dp cue dai ?

Hoat ddng 2 Xac dinh vi tri cac van giao thoa va khoang van HS thao luan theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua.

Ke AH vudng gde vdi Sj, S2, ta cd :

S,H = x—;S2H = x + -' 2 ^ 2

va di = X — + D^

di =

i2 .2

x + -2

+ D '

df -d^=(d, -d2)(d ,+d2) = 2ax

Mat khdc; A rat gdn O va D » a nan :

(d,+d2)=«2D

/ .. ax = > ( d | - d 2 ) - 5 -

GV nau cau hdi vd vdn di cdn nghian cflu - Hay tim dieu kien dd diem A tran man quan sat trong thi nghipm Y Ang la mpt van sang? Tfl dd xac dinh khodng each gifla hai van sang lien tiep, hai vdn tdi lian tia'p ?

GV nau cac cau hdi gpi y - Trong thi nghiem, khoang each a gifla hai ngudn sang rdt nhd so vdi khoang each tfl hai ngudn sang tdi man quan sat. Vi tri ciaa didm A dupe xac dinh theo d|, d2, a va D nhu the' nao ?

89

Didm A la van sang khi

(d,-d2) = k? vdi k la mpt sd

nguyen {k = 0; ±1; ±2...)

Suy ra vi tri van sang tran man E la

, A.D x^=k —

a

Didm A la van tdi khi

(d,-d2) = [k + iJA.

vdi k la mpt sd nguyan (k = 0;±l;±2...)

- Khoang each gifla hai van sang lian tie'p k va k+1 la

., ,v?.D , ?.D A.D (k + 1) k — = —

a a a

HS tie'p thu, ghi nhd

- Van sang trong giao thoa anh sang gidng nhu diem nao trong giao thoa sdng nudc ? Tfl dd suy ra dieu kian dd diem A la van sang ? Didu kian dd diam A la van tdi ?

GV thd che' hoa kia'n thflcJ

- Vi tri cua cac van sang tran man E ;

, XD x =k —

a vdi k la mpt sd nguyan

(k = 0;±l;±2.. .)

Tai diem O (x = 0) ta cd van sang flng vdi k = 0, gpi la van sang trung tam (cdn gpi la vdn sang chinh gifla hay vdn sd 0). Hai ban van sang trung tam la eac van sang bSc 1, flng vdi k - ±1; rdi ddn van sang bac 2, flng vdi k = +2...

- Cdn chu y rdng, vj tri cua van sang la vi tri ciia ehd sang nha't cua van ( tfl vj tri dd, dp sang se giam ddn cho den bang 0 tai van tdi).

90

- Khoang each gifla hai van sang (hoac hai van tdi) canh nhau gpi la khoang van. Ki hiau la i.

. XD 1 =

Hoat ddng 3

Tim hieu each do budc sdng anh sang bang phuong phap giao thoa. Tim hieu budc sdng va

mau sac anh sang


- Sfl dung phucmg phap giao thoa dd do gian tiep budc sdng cua mdt anh sang don sac bang each: sfl dung anh sang don sdc dd trong thi nghiam ciia I-ang, do khoang van giao thoa i va cac khoang each D, a. Tfl dd thay vao cdng thflc . XD 1 = da tim X.

- Viec xae djnh dupe budc sdng cua anh sang don sac trong khong khi giup ehung ta xae djnh dupe budc sdng ciia anh sang don sdc dd trong chan khdng bdng cdng thflc :

n

GV nau cau hdi dd HS tim hidu each do budc sdng anh sang bang phuong phap giao thoa

- Hay thia't kd phuong an thi nghiem de

do budc sdng cua mpt anh sang don sdc ?

GV nau eau hdi gpi y

- Liau cd the sfl dung phuong phap giao

thoa de do budc sdng anh sang dupe

khdng?

- Ne'u sfl dung phuong phap giao thoa, ta cd thd do trye tiep budc sdng cua anh sang dcm sdc dupe khong ?

- Mudn xac djnh budc sdng eua anh

sang dcfn sdc bang phucmg phap giao

thoa thi ta cdn phai xac djnh nhung dai

lupng nao ?

- Mudn xac dinh budc sdng cua anh

sang don sac trong mdi trudng cd chidt

sudt n ta phai lam the' nao ?

GV thong bao

- Ket qua do budc sdng anh sang don

sdc khae nhau cho thdy rang:

Mdi anh sang don sdc cd mpt budc sdng xac dinh.

91


Mpi anh sang don sac ma ta nhin thay

ddu cd budc sdng trong khoang tfl

chirng 0,38 im (anh sang tim) ddn

0,76 m (anh sang dd).

Trong vung anh sang nhin thdy, ngudi ta da phan djnh phdng chflng khoang budc sdng cua bay mau ehinh tran quang phd mat trdi nhu bang 37.1.

Hoat ddng 4

Tim hieu su phii thupc cua chie't suat cua mdi trudng trong sudt

vao tan so va budc sdng anh sang


- Chia't suat cua moi trudng trong sudt phu thupc vao tdn sd va budc sdng anh sang. Vdi mpt mdi trudng trong sudt nhdt djnh, chia't suat flng vdi anh sang cd budc sdng cang dai thi cd gia tri cang nhd hcfn chidt sudt img vdi anh sang cd budc sdng ngan.


GV nau cau hdi dd HS tim hieu sy phu thude eua chidt sudt cua mdi trUcmg trong sudt vao tdn sd va budc sdng anh sang.

- Can cfl vao kdt qua thi nghipm vd hien tupng tan sac anh sang hay cho nhan xet vd sy phu thupc eua chiet sudt cua mdi trudng trong sudt vao budc sdng anh sang ?

GV thdng bao

- Can cii vao ket qua thi nghiam, ngudi ta ve dupe dudng cong tan sdc, bidu didn sy phu thupc cua chiet sua't cua cac mdi trudng trong sudt vao budc sdng anh sang trong chan khdng. Cae dudng cdng tan sdc cd dang gdn dflng vdi hypebol bac hai flng vdi bidu thflc dai sd eua chia't suat n phu thupc budc sdng X

92

Hoat ddng 5

Cung cd bai hpc va dinh hudng nhiem vu hpc tap tie'p theo

B ' cd dang : n = A + —r-

X^ vdi A va B la hang sd phu thupc vao ban chat ciia moi trudng. - Bia't dudng cong tan sdc, thi tfl phep do chie't suat, ta cd the suy ra budc sdng anh sang.

GV yau cdu HS lam viae vdi phieu hpc tap dd cung cd bai hpc

- HS vd nha lam eae bai tap 1, 2, 3, 4, 5 SGK

- HS dn tap lai cac kie'n thflc ve guong phang, lang kinh, thdu kinh da hpc d chuong trinh ldp 11 THPT va 6n lai phuong phap xac dinh vj tri van giao thoa va khoang vdn.

PHlfiU HOC TAP

cau 1. Nhflng hien tupng nao sau day chflng td anh sang cd ban chat sdng ?

A. Phan xa anh sang.

B. Khuc xa anh sang.

C. Giao thoa anh sang.

D. Mpt hian tupng khae.

Cau 2. Hien tupng giao thoa anh sang la sy chdng chdt cua 2 sdng anh sang thoa didu kian

A. cung tdn sd, cung chu ki.

B. cung bian dp, cung tdn sd.

C. cung pha, cung bian dp.

D. eung tdn sd, dp lach pha khong ddi theo thdi gian.

93

Cau 3. Anh sang lam cd budc sdng trong chan khdng va trong nudc ldn lupt la 0,4861|j.m va 0,3635|im. Chiet sua't tuyat ddi cua nudc ddi vdi anh sang lam la

A. 1,3335. B. 1,3725.

C. 1,3301. D. 1,3526.

Cau 4. Anh sang dd cd budc sdng trong chan khdng la 0,6563|.im, chidt sudt eua nudc ddi vdi anh sang dd la 1,3311. Trong nudc anh sang dd co budc sdng

A. 0,4226|am. B. 0,4931|am.

C. 0,4415^m. D. 0,4549^m.

cau 5. Anh sang dupe dung trong thi nghiem lang cd budc sdng 0,5pm, hai

khe sang each nhau 0,5mm va each man 2m. Khoang each van la

A. 2,0mm. B. 1,5mm.

C. 2,2mm. D. 1,8mm.

94

BAI38

BAI TAP vt GIAO THOA A N H SANG

I-MUCTlfiU

1. V6' ki#'n thflc

- van dung cac e6ng thflc vd giao thoa anh sang de lam mpt sd bai toan dcm gian. - Hidu dupe mpt sd phuong phap tao ra hai ngudn sang ket hpp tfl dd quan sat dupe hinh anh giao thoa. Bidt each xac djnh khoang van va sd van quan sat dupe trong mpt sd tructtig hpp cu the.

2. V§' ki n5ng

- Ren luyen ki nang giai bai toan vd giao thoa anh sang. - Ren luyan kl nang giai thich cac hien tupng vat li vd giao thoa anh sang.

n - C H u X N B I

Giao vien

- Chudn bi phieu hpe tap cho HS.

- Ve hinh 38.2 va 38.3 SGK trdn gia'y khd AQ.

Hpc sinh

- HS on tap lai cac kien thflc vd guong phang, lang kinh, thdu kinh da hpc d chuong trinh ldp 11 THPT va dn lai phuong phap xac dinh vi tri van giao thoa va khoang van.

Ill - THlft- Kfi HOAT D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chu^n bi dieu kien xuat phat

HS suy nghl ca nhan tim cdu tra ldi

Trp giiip cua giao vi^n

GV ndu cau hdi kidm tra kien thflc cu

- Viet cdng thflc xac dinh vi tri van sang, van tdi.

- Thiet lap edng thflc tinh khoang van.

95

Hoat ddng 2

Ren luyen cong thflc tinh khoang van va cdng thflc xac dinh vi tri van sang, van tdi HS lam bai tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua

a) Ta cd - 6

1 = ?.D 0,5.10"".3

10 -3 = 1,5mm.

b) Vj tri van sang bac 2 :

Xj = k 2i = 3 m m .

a

GV yau cdu HS lam bai tap 1 trong phia'u hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua.

Hoat ddng 3 Lam bai toan giao thoa vdi luong lang kinh HS lam bai tap theo nhdm, sau dd dai dien nhom lan bao cao ket qua

(ê tia sang di tfl S, sau khi di qua lang kinh Aj bj lech mpt gde : A - (n - 1)A vd phia day ciaa lang

kinh. Hai anh ao Sj, Sj eua S qua hai lang kinh dUpe dung nhu hinh ve.

GV yau cdu HS lam bai tap 2 trong phia'u hpe tap theo nhdm, sau dd dai dien nhdm lan bao cao ka't qua.

GV nau cac cau hdi gpi y - De cd hien tupng giao thoa cdn phai ed hai chum sang gap nhau va hai chum sang dd phai dupe phat ra tfl hai ngudn ka't hpp. Hai ngudn ka't hc^ trong trudng hpp nay la gi ?

96

- Liau rdng hai ngudn kdt hpp ed thd la hai anh eua ngudn sang didm S tao bdi

hai tha'u kinh dupe khong?

- Dyng anh eua ngudn S tao bdi hai thdu kinh ?

Vi gde chiet quang nhd nen hai

anh ao S,; S2 cua S qua hai lang

kinh ddi xflng vdi nhau qua SI. Vi

hai didm S|, S2 la anh ciia cung

mpt ngudn sang S nan ehung la hai

ngudn ka't hpp, hai chum sang do

ehung phat ra cd phdn ehung la

P1IP2 nan tran man E se ed hien

tupng giao thoa trong khoang P^P2.

Tacd:

a = SiS2=2.IS. tanA«2d(n-l)A

=> a = 2.50.(1,5-1)20.3.10'

= 0,3cm = 3mm.

XD_X(d + d')

a a

x-4

=>l = w 0,24mm.

Sd van sang nhieu nhat cd the quan sat duoc tren man E la :

N = l + 2 2i

Trong dd: 2i

la phdn nguyan

P P ciia thuong sd ' ^

Mat khae: "' ^ - -

2i

S1S2 d

d' d' => p p = S1S2.— = a.— = 4,2mm

d d

=>N = l7vansang.

- Nhan xet gi vd chum sang phat ra tfl

hai anh ?

- Xac dinh phdn hai chum sang gap nhau.

- Mudn xac djnh dupe khoang van ta phai xae dinh dupe nhflng dai lupng nao ?

- Mudn xac djnh dupe sd van sang quan

sat tran man ta lam thd nao?

- Hay tinh sd van sang quan sat tran nfla

vung P1P2? Tfl dd suy ra sd van sang

tren ca vung xay ra giao thoa?

- van tmng tam la van sang hay van tdi ?

TKBGVLyi2C(NC) 97

GV thdng bdo - Thyc ra, do hian tupng nhidu xa nen cdc

van d gdn Pj, P2hdu nhu khdng quan sat

dupe nan sd van thyc su quan sat dupe thudng nhd hem N chimg vai van.

Hoat ddng 4

Lam bai toan giao thoa vdi luong thdu kinh Bi - a

HS lam bai tap theo nhdm, sau dd dai dian nhdm lan bao cdo ket qua

Hai anh F|,F2eua F qua hai nfla

thdu kinh la hai ngudn ka't hpp. Hai

chum sdng do hai ngudn Fi,F2

phat ra gap nhau se giao thoa. Vung giao thoa tran mdn E Id P,P2.

GV yau cdu HS lam bai tap 3 trong phia'u hpc tap theo nhdm, sau dd dai dian nhdm lan bao cao ka't qua.

GV nau cac cau hoi gpi y - Di cd hian tupng giao thoa cdn phai cd hai chum sang gap nhau va hai chiim sang dd phai dupe phat ra tfl hai ngudn ka't hpp. Hai ngudn kdt hpp trong trudng hpp nay la gi ?

F ^

d

L.

0,

0 :

1 ,

>^'

M ^

D

E

P.

P2

- Liau rdng hai ngudn kdt hpp cd thd la hai anh cua ngudn sang didm F tao bdi hai thdu kinh dupe khdng ?

- Dyng anh cua ngudn F tao bdi hai thdu kinh ?

Khoang each tfl F1F2 ddn O la :

d' = df ^ 60.20

d - f " 6 0 - 2 0 = 30em.

98

Hai tam giae F0,02va FF(F2ddng

dang nan :

F.F l i2 _ FF,

O1O2 FO

=>F,F2-a = e

a : > — = •

e

d + d'

d + d'

= 3mm.

Tfl hinh ve ta tha'y dd quan sat dupe hian tupng giao thoa thi man E phai dat trong viing hai chum sang gap nhau nan man E phai dat xa thdu kinh hon didm I. Hay D>OL

Mat khae hai tam giac IL,L2 va

IF1F2 ddng dang nan :

FtF2 _ IH

L,L2 10

_ L,L2-FiF2 1 0 - I H

L,L2 10

(L + e) => 10 = d' -i '- =* 33,1cm.

L + e - a

Vdy gia tri nhd nhat cua D phai 33,1cm.

Khoang van:

i = -^^ ^ « 0,27mm.

la

FF.Fj Vi hai tam giac

FP1P2 ddng dang nan ta cd :

P1P2 _ D + d

va

0,02

D + d ^ => P]P2 = e—-— = 8mm.

- Xac djnh vung hai chum sang gap nhau ? Tfl dd suy ra vi tri dat man E dd quan sat dupe hien tupng giao thoa tran man.

- Mudn xac dinh dupe khoang van ta phai xac dinh dupe nhflng dai lupng nao ?

- Xac dinh be rpng vung giao thoa bang each nao ?

- Hay dya vao tinh chat ddng dang cua

hai tam giac FFjFj va FP1P2 dd xac

dinh be rpng eua vung giao thoa.

99

Sd van sang nhieu nhat cd tha quan sat duoc tran man la

N = l + 2 PiS_ 2i

! 29 van.

PHlfiU HOC TAP

D \<r • >

O

c a u 1. Trong thi nghiem ve giao thoa anh

sang, cac khe S, va S2 dupe chieu

sang bdi anh sang don sdc. Khoang

each gifla hai khe a = 1mm. Khoang

cdch gifla mat phang chfla hai khe

va man quan sat E la D = 3m.

a) Bia't budc sdng cua chum sang don sdc la >, = 0,5|im. Hay tinh khoang

van giao thoa.

b) Hay xac djnh khoang van bac 2 tran man quan sat.

c a u 2. Hai lang kinh Aj, A2 cd gde chiet quang A ddu bang 20' cd day B ehung, dupe lam bing thuy tinh, chie't sudt n =1,5. Mpt ngudn sang didm S dat trong mat phang cua day B each hai lang kinh mpt khoang d = 50cm phat anh sang don sac, budc sdng X = dOOnm. Mpt man E each hai lang kinh mdt khoang d' = 70em.

a) Chflng minh rang, trdn man E ta quan sat dupe mpt he van giao thoa.

b) Tinh khoang each i gifla hai van sang lian tiep va sd van ed thd quan sat

dupe, cho l'«3.lO"'^rad..

cau 3. Mpt thdu kinh cd tiau ey f = 20cm, dudng kinh vanh L = 3cm dupe cua lam doi theo mpt dudng kinh. Sau dd hai nfla thdu kinh dupe tach ra xa nhau mpt khoang e = 2mm (nhd chen vao gifla mpt spi day hoac thdi kim loai). Mpt khe sang hep song song vdi dudng chia hai nfla thdu kinh, dat each dudng ay mpt khoang d = 60cm. Khe sang F phat anh sang dcm sac cd budc sdng X = 0,546|.im. Van giao thoa dupe quan sat tran man E, dat each hai nfla Ihau kinh mpt khoang D.

a) Mudn quan sat dupe eae van giao thoa tran man E, thi D phai cd gia tn nhd nha't la bao nhiau ?

b) Cho D = 1,8m, tinh khoang van va sd van sang quan sat dupe tran man. :

100

BAI39

MAY QUANG FH6 - CAC LOAI QUANG FH6

I-MUCTlfiU

1. V ' ki^'n thflc

- Trinh bay dupe nguyan tde cdu tao eua may quang phd lang kinh va neu dupe tac dung cua timg bp phan cua may quang phd. Hidu dupe nguyan tac boat dpng cua may quang phd.

- Nam dupe khai niem quang phd lian tuc, cac dac diem chinh va nhflng flng dung chinh ciaa quang phd lian tuc.

- Hieu dupe khai niem quang phd vach phat xa, ngudn phat, nhiJng dac didm va cong dung ciia quang phd vach phat xa. Didu kien dd cd quang pho vach phat xa.

- Hieu dupe khai niem quang phd vach hdp thu, each thu va dieu kien dd thu dupe quang phd vach hap thu.

-Nam dupe npi dung djnh luat Kiee-sdp.

- Hieu dupe phep phan tich quang phd va sy tien Ipi cua nd.

2. Vi ki nSng

- Ren luyen ki nang giai thich hian tupng vat li. - Ren luyan kl nang thidt kd, tim hidu flng dung kl thuat vat li.

- Ren luyan kl nang lam bai tap trac nghiem khach quan nhidu lya chpn.

II-CHUXNBI

Giao vien

~ Ve hinh 39.1 SGK tran giay khd AQ-

- Chuan bj mpt sd anh ehup ve quang phd lian tuc, quang phd vach phat xa va quang phd vach hdp thu.

Hpc sinh

- On tap lai Bai 35 va cac kidn thflc vd lang kinh, thdu kinh.

101

Ill - THI£T Kfi HOAT D O N G DAY HOC


Hoat ddng 1

Kiem tra, ehuin bj dieu kien xua't phat. Dat van de

HS suy nghl ea nhan tim cau tra ldi

HS nhan thflc dupe vdn di cua bai

hpc

Hoat ddng 2

Tim hidu ca'u tao va nguyen tac

boat dpng cua may quang phd


- Cd the sfl dung lang kinh dd lam dung cu tach anh sang phflc tap thanh cac thanh phdn don sdc khae nhau.

Trp giup cua giao vi^n

GV nau cau hdi kidm tra kidn thflc cu - Trinh bay hipn tupng tan sac anh sang va giai thich hipn tupng.

Dat van de : De nghian cflu cae thanh phdn don sac cua mpt chum sang, ngudi ta da cha' tao ra mpt loai mdy cd tan gpi la may quang phd. Vay may quang phd la gi ? Bai hpc ngay hdm nay se nghian. cuu loai may dd.

GV nau eau hdi de HS thidt ke may

quang phd

- Dd nghian cflu thanh phdn cdu tao cua mpt chum sang phflc tap cdn phai ed mpt dung cu diing de phdn tich chiim sang dd thanh nhflng thanh phdn don sac khae nhau. Hay thiat ke dung cu dd ?

GV nau cae cau hdi gpi y

- Cd each nao de tach mpt chum sang phflc tap thanh nhflng thanh phdn don sdc khae nhau?

- Trong cac dung cu quang hpc, dung

cu nao cho phep ta lam dupe viae dd.

- Tai sao ndi anh sang trdng dupe cdu tao tfl vd sd cac mau don sdc ? Thi nghiam nao cho bia't didu dd.

102

HS thao ludn ehung todn ldp Dung cu cd ca'u tô bdi ba bp phdn chinh:

- Ong chuan trye la bp phdn cd dang mdt cai dng tao ra chum tia sang song song. Nd cd mpt khe hep F nam d tiau dian eua mpt thdu kinh hpi tu Lj. Chum sang phat ra tfl ngudn S ma ta cdn nghian cihi duoc rpi vao khe F. Chum sang Id ra khdi tha'u khinh L, la mpt chum song song.

- He tan sdc, gdm mpt hoac vai lang k&ih P, cd tac dung phdn tich chum tia song song tfl Lj chidu tdi thanh nhieu chum don sdc song song.

- Budng anh la mpt hpp kin trong dd cd mpt tha'u kinh hpi tu Lj (dat chan chum tia sang da bi tan sdc sau khi di qua lang kinh P) va mpt ta'm kinh anh (dd chup quang phd), hoac mpt tdm kinh md (de quan sat quang phd), dat tai tiau dien cua L2.


GV thdng bdo ~ Mpt trong nhung bp phan cdu tao quan trpng cua dung cu edn thiet kd la lang kinh, lang kinh cd tac dung tach chum sang phflc tap thanh nhflng thanh phdn dcm sdc khae nhau.

GV nau cdu hdi dd HS tim hidu ca'u tao eua may quang phd - Ngoai ra, dung cu edn thia't kd edn dupe ca'u tao bdi eae bd phan khdc. So dd cdu tao nhu hinh 39.1 SGK. Hay cho biet dung cu dupe cau tao bdi nhflng bp phan nao ? Vd tde dung cua cac bp phan dd?


- Ngudn sdng S dat tai vi tri nao? anh

eua nd qua L, b dau ?

- Thd u kinh L2 lam nhiam vu gi ? Tai sao lam dupe didu dd ?

- Hay nau tac dung cua thdu kinh L2? Tai sao tdm kinh anh hoac kinh md phai dat tai tidu dian cua tha'u kinh L2?

GV thd ehd hoa kidn thflc - Dung cu ma ehung ta vfla tim hidu gpi la may quang phd lang kinh. May quang phd la dung cu dung dd phan tich mpt chflm sang phflc tap thanh nhflng thanh phdn don sdc khae nhau.

103


- May quang phd hoat dpng dya tran hien tupng tan sdc anh sang.

- Sau khi Id ra khdi dng chudn

trye, chum sang phat ra tfl ngudn S

ma ta can nghian cflu se trd thanh

mpt chum song song. Chum sang

nay qua lang kinh se bj phan tich

thanh nhieu chum sang don sdc

song song, lach theo eae phuong

khae nhau. Mdi chum dcfn sdc dy

dupe tha'u kinh L2 cua budng anh

lam hpi tu thanh mpt vach tren tiau

dien cua L2 va eho ta mpt anh that

cua khe F, dd la mpt vach mau.

Cac vach mau nay dupe chup tran

kinh anh hoac hien lan kinh md va

nd la mpt thanh phdn anh sang don

sdc do ngudn S phat ra.


Hoat ddng 3

Tim hieu quang phd lien tuc


- Quang phd eua anh sang trang la

ha thdng cac dai mau sdc bia'n

thien lian tuc tfl dd da'n tim.

GV nau cau hdi de HS tim hieu nguyan tac hoat dpng eua may quang pho lang kinh

- Dya vao so dd cdu tao cua may quang phd lang kinh, hay cho bia't may quang phd lang kuih hoat dpng dya tran hien tupng nao ? Trinh bay nguyan tde hoat dpng ciaa nd ?

GV thdng bao

- Tap hpp cac vach mau dd tao thanh

quang phd eua ngudn S.

GV ndu cau hdi dd HS tim hidu quang

phd lian tuc

- Nhan xet gi vd quang phd cua anh sang trdng do mat trdi hoac do den day tde ndng sang phat ra ?

GV thong bao

- Quang phd cua anh sang trdng do Mat Trdi, bdng den cd day tde ndng sang phat ra la quang phd lian tuc.

104

- Chdt khi va chat rdn khi d nhiat do cao phat ra anh sang ed quang phd lian tuc.


- Quang phd gdm nhieu dai sang, mau

sdc khae nhau, ndi lidn nhau mpt each

hen tuc dupe gpi la quang phd lian luc.

GV nau eau hdi dd HS tim hidu ngudn

phat anh sang cd quang phd lian tuc

- Hay cho bidt, trong cae chat rdn, long, khi chat nao phat ra anh sang cd quang phd lian tuc ? Dieu kien de ehung phat ra quang phd lian tuc ?

GV thdng bao

- Thi nghiam eho tha'y : eac eha't rdn, chat long va nhiJng chat khi cd khdi lupng riang ldn khi bj nung ndng phat ra quang phd lian tuc.

- Mpt dac didm quang trpng cua quang phd lian tuc la nd khdng phu thupc vao ban chdt cua vat phat sang, ma ehi phu thupc vao nhiat dp cua vat.

- O mpi nhiet dp, vat deii bfle xa. Khi nhiet dp tang ddn thi cudng dp bfle xa cang manh va midn quang phd lan ddn tfl bfle xa ed budc sdng dai sang bfle xa cd budc sdng ngdn.

Hoat ddng 4

Tim hieu quang phd vach phat xa va quang phd vach hap thu


- Quang phd cd cae vach mau

khong lian tuc ma ridng le, ngan

each nhau bang nhflng khoang tdi.

GV cho HS xem mpt sd hinh anh quang phd vach phat xa cua hidrd, thuy ngan ... Yau cau HS so sanh su khae nhau cua quang phd vfla dupe xem (quang phd vach phat xa) vdi quang phd lian tuc cua anh sang trdng ?

105


HS thao luan ehung toan ldp - Quang phd cd ndn la quang phd lian tuc nhung bi thia'u mdt mdt sd vach mau.


GV thdng bao - Quang phd nhu vay la quang phd vach phat xa. - Quang phd ehi chfla cae vach mau riang le, ngan each nhau bang nhflng khoang tdi, dupe gpi la quang phd vach phat xa.

- Quang phd vach phat xa do cac chdt khi, hay hoi d dp sudt thdp phat ra khi bi kich thich (khi ndng sang, hoac khi eo ddng dien phdng qua).

- Thyc nghiam cho thdy, mdi chdt khi bi kich thieh phat ra eac bfle xa cd budc sdng xac dinh va eho mdt quang ph6 vach phat xa riang, dac trung cho nguyan td ay.

GV cho HS xem mpt sd hinh anh quang phd vach hdp thu eua hidrd, thuy ngan ... Yau cdu HS so sanh sy khae nhau ciia quang phd vfla dupe xem (quang phd vach hdp thu) vdi quang phd lian tuc cua anh sang trdng ?

GV thdng bao

- Di ed dupe quang phd nhu vay ngudi ta lam nhu sau: chidu mpt chum sang trang do mpt den cd day tde ndng phat ra vao khe eua mpt may quang phd, ta thu dupe mpt quang phd lian tuc tran tdm kiiih cua budng anh. Ndu tran dudng di eua chum sang dd ta dat mpt den dng thuy tinh cd chfla hoi nalri thi tha'y quang phd lian tuc xudt hien mpt vach tdi (thyc ra la hai vach tdi ndm sat canh nhau) d dung vi tri cua vach vang

106

Hoat ddng 5

Tim hieu djnh luat Kiec - sop va tac dung cua viec phan tich quang phd

HS thao luan ehung loan ldp

- Trong thi nghiem tao ra quang

phd vach hap thu cua natri cdn

phai dat den hcri natri cd nhiet dp

thap hon nhiet dp cua ngudn sang

Iran dudng di cua chum sang trdng

phat ra tfl den day tde ndng sang.

Khi dd hoi natri da bi kich thich.

Vi vay, khi tdt ngudn sang trdng thi

hoi natri se phat ra quang phd vach

phat xa cd vach mau gidng nhu mau

da bi mat Iran nen quang phd lian

tuc d quang phd vach hdp thu.

trong quang phd phat xa cua natri. Dd chinh la quang phd vach hdp thu eua natri. - Vay quang phd lian tuc, thidu mpt sd vach mau do bj chdt khi (hay hoi kim loai) hdp thia, dupe gpi la quang phd vach hap thu cua khi (hay hoi) dd.

- Cdn luu y rdng, didu kien de thu dupe quang phd vach hdp thu la nhiet dp eua dam khi hay hoi hdp thu phai thap hon nhiat dp cua ngudn sang phat ra quang phd lian tuc.

GV nau cau hdi dd HS tim hidu djnh luat Kia'c-sdp

- Trong thi nghiem tao ra quang phd vach ha'p thu cua natri, bang mpt thao tac thi nghiam hay tao ra quang phd vach phat xa eua nd ?


- Hay nau sy khae nhau gifla quang phd

vach hdp thu va quang phd vach phat xa

eua nguyan tfl natri?

- Tai sao trong thi nghiem tao quang

phd vach hdp thu phai dat den hoi natri

tran dudng truyen cua chum sang trdng ?

- Dieu kien de ed quang phd vach phat xa la gi ?

107


HS thao luan ehung toan ldp - Can cfl vao quang phd vach hdp thu cua chdt khi hay hoi eua hdn hpp hay hpp chdt, xem vach mau bj hap thu cua quang phd dd suy ra sy cd mat cua cac nguyan td trong hdn hpp hay hpp chat.


G V the che hoa kia'n thflc - Vay d nhiet dp xac djnh, mot vat chi ha'p thu nhflng bfle xa nao ma nd cd kha nang phat xa, va ngupe lai, nd chi phat bfle xa nao ma nd ed kha nang hdp thu. Day chinh la npi dung cua djnh luat Kia'c-sdp. - Djnh luat nay dupe nha bac hpc Kia'c-sdp tim ra khi khao sat quang phd vach ha'p thu cua nhDtig chdt khae nhau va ddu tha'y ehung cung la quang phd vach, nhung vach phd sang khi phat xa da trd thanh vach tdi trong quang phd ha'p thu. Hien nay dd gpi la sy dao vach quang phd.

• , ; . ; ^ |

GV nau cau hdi de HS tim hidu tac dung cua viec phan tich quang phd - Lam tha' nao dd nhan biet dupe sy cd mat eua nguyan td trong mpt hdn hpp hay hpp ehdt ? GV thdng bao - Viec lam nhu tran gpi la phdn tich quang phd. Phan tich quang phd la phucfng phap vat li dung dd xac dinh thanh phdn hoa hpc cua mpt chdt, dya vao viec nghian cflu quang phd anh sang do chat a'y phat ra hoac hap thu. - Phan tich quang phd dinh tinh cd uu diem la: eho ket qua nhanh, cd dp nhay cao va ed the eung mpt luc xac dinh dupe sy cd mat cua nhidu nguydn td. - Ngoai ra, ngudi ta cdn phan tich djnh lupng di bia't dupe cac ham lupng ciaa cac thanh phdn nguyan td cd trong mdu bang each do cudng dp eae vach quang phd phat xa, hoac hdp thu cua nguyan tda'y. ^

108

Hoat ddng 6


GV yau cdu HS lam viec vdi phia'u hpc tap dd cung cd bai hpc

- HS ve nha lam cac bai tap 1, 2, 3, 4 SGK

- HS dn tap lai cae kidn thflc vd quang phd cua anh sang trdng va sdng dien tfl.

PHlfiu HOC T A P

cau 1. Phat bidu nao sai khi ndi vd quang phd lian tuc ?

A. Quang phd lian tuc khdng phu thupc vao thanh phdn cdu tao cua ngudn sang.

B. Quang phd lian tuc phu thupc vao nhipt dp cua ngudn sang.

C. Quang phd lidn tuc la nhflng vach mau riang biat tran nhflng ndn tdi

D. Quang phd lian tuc do eac vat rdn, long hoac khi cd ti khdi ldn khi bj nung ndng phat ra.

Cau 2. Anh sang cd tinh chat sdng vi

A. khi cho anh sang trang di qua lang kinh thi bj tach ra thanh nhidu chum sang cd mau sac khae nhau.

B. khi cho anh sang don sdc di qua lang kinh thi khong bi tan sdc.

C. anh sang ed thd giao thoa va cho nhflng vach sang tdi xen ke nhau tran man.

D. ta cd thd tdng hpp anh sang trdng tfl vd sd cae anh sang don sdc cd mau bia'n thian lien tuc tfl dd den tim.

cau 3. Co quang phd lien tuc la do

A. eac vat rdn long hoac khi cd ti khdi ldn khi bi nung ndng phat ra. B. chat long d nhiet dp thap phat ra.

C. dam khi hay hoi d ap sudt thdp bi kich thieh phat ra. D. cac vat rdn d nhiet dp thdp phat ra.

109

Cau 4. Quang phd nao la quang phd vach phat xa trong cac quang phd sau ?

A. Quang phd ciaa mieng sdt dupe nung ndng den nhiet dp la 2000K. B. Quang phd cua den hoi thuy ngdn.

C. Quang phd cua day tde bdng den khi thdp sang.

D. Quang phd cua anh sang mat trdi.

Cau 5. Tran dudng di cua anh sang trdng chia'u den may quang phd ta dat mat den hoi natri nung ndng (nhiet dp thdp hon nhiet dp cua ngudn sang trdng) ta se

A. thu dupe quang phd lian tuc.

B. thu dupe quang phd vach phat xa.

C. thu dupe quang phd vach hdp thu.

D. khdng thu dupe quang phd.

Cau 6. Budc sdng anh sang dupe do tfl thi nghiam nao ?

A. Thi nghiam tan sac anh sang eua Niu-ton.

B. Thi nghiam vd tdng hpp anh sang trdng.

C. Thi nghiem giao thoa anh sang vdi khe I-ang.

D. Thi nghiam ve anh sang don sac.

cau 7. Khi sfl dung phep phan tich quang phd ngudi ta cd thd xac dinh dupe

A. hinh dang cfla mdt vat.

B. nhiet dp cua mpt vat.

C. thanh phdn cdu tao cua cae ehdt trong vat.

D. hinh dang va nhiat dp cua vat.

no

BAI40

TIA H 6 N G NGOAI - TIA TLT NGOAI

I-MUCTlfiU

l.va'kie'n thflfc

- Hidu dupe ban cha't tia hdng ngoai va tia tfl ngoai, ngudn phat ra ehung. - Dua ra dupe dy doan ngoai viing anh sang nhin thdy trong quang phd lian tuc con cd eac bfle xa khdng nhin tha'y, dd xudt dupe phucmg an thi nghiam kidm tra dy doan. - Nau dupe cac tinh chdt cua tia hdng ngoai va tia tfl ngoai, dd xudt dupe phuong an thi nghiam kidm tra eae tinh ehdt eua tia hdng ngoai va tia tfl ngoai.

2, Vi ki n3ng

- Ren luyan ki nang dua ra dy doan cd can cfl. - Rdn luyan kl nang thia't kd phucmg dn thi nghiem kidm tra dy doan. - Ran luyen ki nang quan sat GV tien hanh thi nghiam va rut ra ka't luan. ~ Ren luyan ki nang giai thieh cac hian tupng vat li.

II-CHUXNBI

Gido vien

- Chudn bi bd thi nghiam nghian cflu tinh chdt tia hdng ngoai, tfl ngoai do Khoa Vat li trudng DHSP Ha Npi cha' tao (ndu cd).

Hoc sinh

- HS dn tap lai cdc kidn thflc vd quang phd cua dnh sang trdng vd sdng didn tfl.

m - THlfiT Kfi HOAT D 6 N G DAY HOC 1 • —


, Hoat ddng 1 *

Ki m tra, chudn bj dieu kian xua't phat HS suy nghl ca nhan tim cau trd ldi

Trp giiJip cua giao vi^n

GV nau cdu hdi kidm tra kidn thflc cu The nao la hian tupng TSAS ? Giai thich hien tupng.

I l l

- La hian tupng anh sang trdng khi di qua lang kinh bi tach thanh nhidu mau.

- Nguyan nhan do anh sang trang gdm nhieu anh sang dcm sdc cd budc sdng khae nhau, chiet sudt cua lang kinh tang flng vdi anh sang cd budc sdng nhd di.

Hoat ddng 2

Nghien cflu ve cac bfle xa khdng

nhin thay

HS thao luan theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua dy doan

- Dy doan: ehdc cd thd ed mpt sd bfle xa ma mdt ta khdng thdy duoc

- Giai thich : anh sang nhin thdy cd budc sdng gidi ban trong pham vi hep tfl 0,4|im den 0,76|im thi chae han vdn cdn bfle xa nao dd ngoai vung nay.

- Tia hdng ngoai trong dieu khien tfl xa, chup tia X, dng nhdm hdng ngoai...

GV nau eau hdi ve vdn dd can nghian

cflu

- Trong thi nghiem vd hien tupng tan sdc anh sang, ngoai cae bfle xa quan sat dupe tran man cdn ed nhung bfle xa nao khae khdng ?

GV ,nau eau hdi dd kiem tra xem dy doan cua HS cd phai la dy doan cd can cfl hay khong

- Tai sao cae em dy doan la ed ?

- Ldy vi du chflng td cd bfle xa nao dd cd tdn tai ma mdt ta khdng thdy.

GV nau eau hdi thiet ke phUOng an thi nghiem

- Nhung liau vdi den dung spi dot ndng trong thi nghiem tan sdc anh sang Uau co the cd bfle xa nim ngoai vung anh sang

112


- Ta tidn hanh thi nghiam TSAS. Sau dd dua mpt ddu thu nao dd cd thd thu dupe nhieu loai bfle xa ra ngoai vung anh sang nhin tha'y xem ddu thu cd phat tin hiau hay khdng.

HS quan sat thi nghiem va rut ra kdt ludn

- HS lan bd tri va tidn hanh thi nghiam. Kdt qua thi nghiam: Khi dua ddu thu ra tran vung anh sang dd va dudi vung anh sang tim ddu tha'y kim tinh dian kd lach.

- Bfle xa khdng quan sat tran viing dd cd budc sdng ldn hon 0,76^m ; bfle xa khdng quan sat dudi vung tim cd budc sdng nhd hon 0,38tim.

nhin thdy khdng ? Hay dua ra cae phuong an thi nghiam dd phat hien ed tdn tai hay khdng eac bfle xa ngoai vung nhin thdy eua anh sang bdng den spi ddt ?

GV nau cdu hdi gpi y

- Khi didu khidn tivi bang didu khien tfl xa, tia hdng ngoai dupe mpt dau thu trong tivi thu lai. Vay neu chflng ta cd mpt ddu thu nhu vay thi se phai tien hanh thi nghiam nhu thd nao ?

GV gidi thiau cac thiet bi thi nghiam, yau cdu mpt HS ldp rap thi nghiam va tia'n hanh thi nghiem cho ca ldp cung quan sat va rut ra ket luan

- vay tdn tai bfle xa khdng nhin thdy, d phia tran vung dd va dudi vung tim. Hai loai bfle xa nay se cd budc sdng ed gia tri trong khoang nao ?

TKBGVLyi2«(NC) 113


Hoat dong 3

Nghien cflu cac tinh chat va umg dung cua tia hong ngoai


- Tia hdng ngoai ed eac tinh chat : khuc xa, phan xa, giao thoa, nhidu xa tac dung nhiat, tac dung quang dien. - Vi tia hdng ngoai la bfle xa cd budc sdng gan anh sang nhin tha'y do dd cd mpt sd tinh chat gidng anh sang.

- Dung den phat tia hdng ngoai, tfl ngoai ehie'u vao guong va chia'u vao mdi trudng trong sudt nao dd. Dung ddu thu hdng ngoai, tfl ngoai dd phat hifn tia phan xa va tia khuc xa.

- Tac dung nhiet : Dung mpt nhiet ke di kidm tra xem khi chia'u tia hdng ngoai vao ed tang nhiat dp hay khdng...

GV thdng bao - Cac bfle xa dd ngudi ta dat tan la bfle xa hdng ngoai va bfle xa tfl ngoai:

Bfle xa hdng ngoai la bfle xa khdng nhin thdy cd budc sdng dai hon 0,76|am da'n khoang vai milimet.

Bfle xa tfl ngoai la bfle xa khdng nhin tha'y ed budc sdng ngdn hon 0,38nra

da'ncd I0~^m.

GV nau eau hdi vd vdn dd cdn nghian cflu Theo cac em thi tia hdng ngoai co nhflng tinh chat nao ?

GV nau cau hdi kidm tra xem dy doan ciaa HS cd phai la dy doan ed can cfl khdng.

- Theo cae em tai sao tia hdng ngoai ed nhflng tinh cha't dd ?

GV nau eau hdi thiet ke phucfng an thi nghiem

- Vay em nao ed the thidt kd cae phuong an thi nghiem dd khao sat xem tia hdng ngoai ed cac tinh chdt dd hay khdng ?

114

- Mac quang trd ndi tiep vdi dien ke G va mdc vao ngudn. Khi chia'u bfle xa hdng ngoai vao thi gde lech cua kim dien kd tang

HS quan sat thi nghipm va rut ra ket luan

- Ka't qua tha'y ed tin hieu cua ddu thu khi hflng tia phan xa va khuc xa.

- Nhiat d6 tang khi dat chidu tia hdng ngoai vao, va didn trd cua quang trd thay ddi khi chidu tia hdng ngoai vao.

GV nau eau hdi gpi y - Cdn tac dung quang dian, eae em se dupe hpc d bai sau. Nhung d day thdy cd mpt quang trd, nd giam dipn trd khi chia'u bfle xa cd budc sdng nhd hon hoac bang budc sdng hdng ngoai. Em nao ed thd thiet kd phuong an thi nghiam kidm tra ?

GV yau cdu mpt hoac hai HS lan bd tri thi nghiam va tidn hanh thi nghipm

115


- Ung dung trong didu khidn tfl xa va trong den nhin dam la flng dung kl thuat eua tac dung quang dian. Ban than ddu thu phat hien cac bfle xa trong thi nghiem luc ddu cung dya vao tac dung quang dien cua tia hdng ngoai.

- May sa'y khdng phat anh sang nhung vdn cd tac dung nhiet. Den hdng ngoai dd sudi dm mua dong. Didu khidn tfl xa, quan sat ban dam...

GV thd ehd hoa kien thflc

— Nhu vay tia hdng ngoai ed cac tinh

cha't nhu cac em dy doan.

- Tia hdng ngoai cd mpt tinh ehdt

dien hinh la tac dung nhipt. Ngudn

phat tia hdng ngoai thudng la cdc vat

cd nhiat dp. Khi nhiat dp vat du cao

thi ngoai tia hdng ngoai vat edn phat

anh sang nhin thdy.

GV yeu cdu HS thao luan dd dua ra nhflng flng dung eua tia hdng ngoai

116

Hoat ddng 4

Nghian cflu cac tinh ch^t va flng dung cua tia tu ngoai


- Khuc xa, phan xa, giao thoa,

nhidu xa tac dung nhiat, gay tac

dung phat quang mpt sd ehdt, tac

dung sinh li, tac dung quang dian.

- Vi ra ngoai ndng bj den da do tfl ngoai.

Tia tfl ngoai cd budc sdng ngan nan gay tham mpt sd tinh eha't dd...

Mpt hoac hai HS ldn lap rap thi nghiam va tia'n hanh thi nghiem kidm tra.

GV nau cdu hdi ve v§ii dd cdn nghian cflu

- Theo cac em thi tia tfl ngoai cd nhflng tinh chdt gi ?

GV nau cau hdi kiem tra xem dy doan cua HS cd phai la dy doan cd can cfl khdng

- Ngoai nhflng tinh eha't gidng tia hdng ngoai va gidng anh sang nhin tha'y la khuc xa, phan xa, giao thoa, nhidu xa tac dung nhiat, tac dung quang dian. Vay tai sao tia tfl ngoai cdn cd thdm cac tinh ehdt la tac dung sinh li, tac dung phat quang ?

GV yau cdu HS thiet ke phuong an thi nghiam kidm tra

- Cac thia't bi edn thidt eho eac phuong an thi ngiem kidm tra cac tinh chat phan xa, khuc xa, phat quang va tac dung quang dien da dupe chudn bj. Mdi cac em cd phucfng an thi nghiem lan bd tri va tidn hanh thi nghiam.

117

m^^M'r^^^m

r^€

Kdt qua deu phat hian cd cac tinh cha't da neu.

GV gpi y

- Viae tia'n hanh thi nghiam gidng nhu thi nghiem nghian cflu tia hdng ngoai, tuy nhian can phai thay den phat tia hdng ngoai bang den phat tia tfl ngoai.

GV thong bao

- Tinh cha't ndi bat cua tia tfl ngoai la

118


Hoat ddng 5


HS suy nghl ca nhan tim eau tra ldi

tinh chdt phat quang mdt sd eha't. Tia tfl ngoai gay tac dung sinh li do dd khdng dupe dd tia tfl ngoai chieu trye tia'p vao CO thd , dac bipt khdng nhin trye tiep tia tfl ngoai.

- vat nung ndng tran 2000°C cd thd phat tham bfle xa tfl ngoai. Cac ngudn phat tia tfl ngoai chu yeu la den hoi thuy ngan, den hd quang.

GV nau cau hdi eung cd bai hpc

- Den dng la den hcri thiiy ngan, theo cae em da sfl dung flng dung gi ma ta vdn ed the nhin dupe anh sang den dng ?

- Giai thich tai sao anh sang bdng den phat ra ea bfle xa hdng ngoai va tfl ngoai ?

- HS ve nha lam cac bai tap 1, 2, 3, 4 SGK.

- On lai cae kien thflc vt tia catdt da hpc dldp 11.

119

BAI41

TLA X. THUYDT DifiN TLT A N H S A N G

THANG SONG DifiN TlT

I -MUCTl£U

1. Vi Viin thflc

- Hidu dupe ban chat tia X, nhde lai dupe each tao ra tia X.

- Nam dupe each tinh cha't va edng dung cua tia X.

- Hidu dupe thuyet dien tfl ve anh sang.

- Hinh dung dupe mpt each khai quat vd thang sdng dipn tfl.

2. Vi ki nang

- Ren luyan ki nang dn luyan kidn thflc cu.

- Ren luyen ki nang dpc tai lieu, tim thdng tin trong tai lieu.

II-C:HUXNBI

Gido vien

- Ve hinh 41.1; 41.3 SGK tran gidy kho AQ.

Hpc sinh

- On lai cac kien thflc ve tia catdt da hpe d ldp 11.

Ill - THifi'T K£' H O A T D 6 N G D A Y HOC


Hoat ddng 1

Kiem tra, chudn bi dieu kien xuat phat. Dat van de

HS suy nghl ca nhan tim cdu tra ldi

Trp giiip cua giao vien

GV neu cau hdi kidm tra kien thflc cu

- Tia catdt la gi ?

- Ne'u tran dudng truyen cua tia catdt ngudi ta dat mpt tam kim loai cd platin thi cd hian tupng gi ?

.120

1 1

HS nhan thflc dupe vdn dd cua bai i hpe ;

Hoat ddng 2

Tim hieu tia Ron - ghen

HS tidp thu, ghi nhd ;

• •! • > • • • - :

HS thao luan ehung toan ldp •

- Cho chum tia catdt trong dng i

phong tia catdt dap vao mpt mieng \

kim loai cd nguyan tfl lupng ldn se i

phat ra tia X.



- Tia X ed kha nang dam xuyan ldn. :

- Tia X tac dung manh lan phim ;

anh.

- Tia X cd tac dung lam phat i

quang mpt sd ehdt. ;

Dat vdn de : Ldp 11 THPT ehung ta da

bie't tia catdt la chum electron ed van tde ldn, khi dap vao vat cd nguyan tfl lupng ldn, bj ham lai va lam phat ra tia Ron-ghen. Vay tia Ron-ghen la gi ? Bai

hpc nay ehung ta se tim hidu didu dd.

GV thdng bao

- Bfle xa cd budc sdng tfl 10 mden

10" m (ngdn hon budc sdng cua tia

tfl ngoai) dupe gpi la tia X hay tia Ron- ghen.

- Ngudi ta cung thudng phan biat tia X cflng (ed budc sdng rait ngdn) va tia X mdm (cd budc sdng dai hon).

GV nau cau hdi dd HS tim hieu each tao

ra tia Ron-ghen

- Cd thd tao ra tia X bdng each nao ?

GV thdng bao

Nha bac hpe Rcm-ghen la ngudi ddu

tian da tao ra tia X nam 1895 bang each

nay. 6ng thdy rdng tia X cd tac dung lam phat quang mpt sd chdt va lam den

phim anh. Va tia X cdn dupe gpi la tia

Ron-ghen.

GV nau cau hdi dd HS tim hieu cae tinh chat cua tia X va edng dung eua nd.

- Hay nau mpt sd tinh chdt cua tia X va fltig dung eua nd ma em bie't.

121

- Tia X ed tac dung sinh li manh: buy diet te bao... Ngudi ta dung tia X dd : chieu, chup dien de chudn doan banh hoac tim ehd xucfng gay, manh kim loai trong ngudi...


Hoat dong 3 Tim hieu thuyet dien tfl ve anh sang HS lam viec ca nhan tim eau tra ldi - Nha bac hpc Mdc-xoen da dya vao sy tuong ty gifla cac tinh chat CLia sdng dien tfl va anh sang va phat tridn thuyet sdng anh sang ciaa Huy-ghen va Fren-nen. - Ban chat anh sang : anh sang la sdng dien tfl cd budc sdng rdt ngdn (so vdi sdng vo tuyen dien), lan truydn trong khong gian.

GV bd sung kidn thflc - Tia X cd kha nang ddm xuyan ldn, ed the xuyan qua tam nhom day vai xentimet nhung lai bj ldp chi day vai milimet chan lai. Vi vay ngudi ta thudng dung chi dd lam cac man chdn tia X. Tia X cd budc sdng cang ngan thi cang xuyan sau, tfle la cang cflng.

- Vi tia X cd tac dung sinh li manh nan ngudi ta edn sfl dung nd dd diet khudn, chfla benh... - Tia X edn dupe dung trong cdng nghiep de kidm tra cac vet nflt, cac bpt khi ban trong cae vat bang kim loai, kidm tra hanh li eua hanh khach di may bay, nghian cflu cdu true vat ran...

GV yau cdu HS dpc mue 2 SGK va tra ldi cae eau hdi sau day de tim hidu thuyet dien tfl ve anh sang - Ai la ngudi dua ra thuydt dian tfl vd anh sang ? C ^ cfl vao dau de dua ra thuyet dien tfl vd anh sang ? - Theo thuyet dien tfl vd anh sang thi ban chdt anh sang la gi ?

122

- Tfl thuya't dien tfl vd anh sang,

Mac-xoen cung da thiet lap dupe

mdi lian he gifla tinh chat dien tfl,

vdi tinh chat quang cua mdi trudng

V

trong dd c la tde dp anh sang trong

chan khdng ; v la tde dp anh sang

trong mdi trudng cd hdng sd dien

moi E va dp tfl tham fi.

- Do tfl thdm cua mdi trudng dupe

do bang ti sd cua cam img tfl trong

mdi trudng dd va cam flng tfl trong

chan khdng do eung mpt ddng

dian gay ra.

- D6 tfl tham eua khong khi )a = 1,

cdn dp tfl thdm ciaa chdt sdt tfl

p , » l .

n = êp,

- Lo-ren-xo chflng td dupe rang e

phu thupc vao tdn sd f cua anh sang

£ = F(f). Nhd dd ma dng da giai

thich dupe sy tan sdc anh sang.

- Cae kdt qua tran da dupe thyc

nghiam chflng minh.

- Mdi ban he gifla tinh chat dien tfl vdi

tinh chat quang cua mdi trudng la gi ?

- Hay cho biet dp tfl thdm cua mdi

trudng dupe xac djnh nhu the nao ? Dp

tfl thdm eua khdng khi va dp tfl thdm

cua cha't sat tfl khae nhau nhu the nao ?

- Chiet sudt eua mdi trudng phu thupc

nhu the nao vao hang sd dien mdi va dp

tfl thdm eua mdi trudng ?

- Lo-ren-xo edn chflng td dupe didu gi ?

- Cho den ngay nay, cac ket qua tran da

dupe chflng minh bang thyc nghiem

chua?

Hoat ddng 4

Nhin tdng quat ve sdng dien tfl. Tim hieu thang sdng dien tfl


GV neu cau hdi dd HS tim hidu each nhin tdng quat ve sdng dien tfl va tim hidu thang sdng dien tfl

123

HS quan sat thang sdng dian tfl dd kiem tra cae sdng dien tfl vfla het ka


Hoat ddng 5


- Hay kd tan eae sdng dien tfl ma em ; bie't theo thfl ty sdng dian tfl ed budc sdng tfl ldn den be? GV cho HS quan sat hinh ve 41.3 vd thang sdng dien tfl de kiem tra

GV bd sung kien thflc .

- Trong thang sdng dien tfl, tia gamma ed budc sdng nhd nhdt, tia nay se dupe hpe d chuong VII.

- Vi cac tia ed tdn sd va budc sdng khae nhau nan ehung cung cd nhirng tinh chat rdt khae nhau. Cae tia cd budc sdng cang ngdn cd tinh dam xuyan cang manh, dd tac dung lan kinh anh, dd lam phat quang eae chat va dd idn hoa khdng khi. Cae tia ed budc sdng dai, ta da quan sat hipn tupng giao thoa.

GV yau cdu HS lam cac bai tap trong phieu hex: tap dd cung cd bai hpc ~ HS ve nha lam eae bai tap 1, 2 SGK

- On lai cac kidn thflc vd khoang van, budc sdng anh sang va do budc sdng anh sang bang phucmg phap giao thoa.

PHlfiu HOC TAP

cau 1. Budi tdi ed thd chup anh eo thd eon ngudi vi d nhiet dp 37°C co thd con ngudi cd the phat ra cac tia A. tia hdng ngoai.

B. tia tfl ngoai.

C. tia Ron-ghen.

D. anh sang nhin thay.

124

Can 2. Dieu nao sai khi so sanh tia hdng ngoai, tfl ngoai va tia Rcm-ghen ?

A. Cung cd ban cha't la sdng dian tfl.

B. Ca ba loai tia tran ddu tac dung lan kinh anh.

C. Tia tfl ngoai cd budc sdng nhd hon budc tia hdng ngoai va tia

Rong-hen.

D. Ca ba loai tia tran deu khong nhin thdy dupe.

Cau 3. Trong eae ka't luan sau, kdt luan nao sai khi ndi ve kha nang giao thoa

cua cac loai tia ?

A. Anh sang nhin thdy dupe cd kha nang giao thoa.

B. Tia tfl ngoai cd kha nang giao thoa.

C. Tia hdng ngoai ed kha nang giao thoa.

D. Tia Ron-gen khong cd kha nang giao thoa vi ed budc sdng nhd.

125

BAI42 .

Thtrc hanh : x A c DINH Bl /dc SONG A N H S A N G

I - M U C T l £ U

1. Ve kie'n thflc

- Thidt kd dupe phuong an thi nghiam do budc sdng anh sang bang phuong phap

giao thoa anh sang.

- Xac dinh budc sdng crua anh sang don sac dya vao hian tupng giao thoa ciaa anh

sang don sac qua khe I- ang.

- Quan sat hian tupng giao thoa cua anh sang trdng qua khe I-ang.

2. Ve ki nang

- Ren luyen kl nang thiet ke phucmg an thi nghiem.

- Ren luyen kl nang su dung cac dung cu thi nghipm dd tao ra he van giao thoa,

ren luyen ki nang phdi hpp viec didu chinh dng quan sat vdi vipc quan sat ha vin

giao thoa.

- Ren luyen kl nang phdi hpp trong viae lam viae nhdm.

- Ren luyan kl nang thu thap sd lieu, xfl li sd lieu...

II-CHUXNBI

Gido vien

- Ve hinh 42.2 va 42.3 SGK tran gidy khd AQ.

- Chuan bj va kidm tra chat lupng eae dung cu d hai phucfng an thi nghiam trong bai thyc hanh.

- Can phai tien hanh trudc eac thi nghiem nau trong bai thyc hanh.

Hpc sinh

- On lai cac kia'n thflc vd khoang van, budc sdng anh sang va do budc sdng anh sang bang phuong phap giao thoa.

126

ni - THifiT Kfi HOAT D 6 N G DAY HOC


Hoat ddng 1

Kidm tra, chuan bi dieu kien

xuat phat. Dat va'n de

HS suy nghl ea nhan tim eau tra ldi

- Cho anh sang don sdc cdn do

budc sdng giao thoa theo thi

nghiem Y Ang. Xac dinh khoang

van i, va cac khoang each D, a. Ap

dung cdng thflc tinh khoang van de

suy ra budc sdng anh sang cdn do.

HS nhan thflc dupe vdn dd eua bai

hpe

Hoat dong 2.

Thiet ke' phuong an thi nghiem

do budc sdng anh sang dd va anh

sang xanh

HS thao luan theo nhdm, sau dd

dai dian nhdm lan bao cao ket qua

- Diing den day tde ndng sang

chieu qua mpt khe hep S. Dat hai

khe hep S,, Sj song song vdi khe S

va nhan anh sang chieu tfl khe S.

Trudc khe S dat mdt kinh Ipc sac

de anh sang chieu tdi khe S, va Sj

la anh sang don sac. Do khoang

vdn i va khoang each D gifla man

hflng van giao thoa ddn hai khe S,,

S2. Tfl do tinh budc sdng cdn do.


GV nau cau hdi kiem tra kien thflc cu

- Trinh bay nguyan tde do budc sdng

anh sang bang phuong phap giao thoa.

Dat vdn de : Hdm nay ehung ta ap dung

phucmg phap nhu vay dd di do budc

sdng anh sang eua anh sang dd va anh

sang xanh.

GV nau cau hdi thiet ke phucfng an thi

nghiem

- Hay thia't ke phucmg an thi nghiem dd

do budc sdng cua anh sang dd va anh

sang xanh ?

127

HS quan sat va tra ldi eac cau hdi

- Sfl dung kinh Ipc sdc dd cdm vao kheL.

- Dat mdt phia sau man M de quan sat ha van giao thoa qua kinh Iflp (5). "

- Trong thi nghiem nay, ta phai djch chuyen man M bang each dich chuyen dng L2 di eac van sang tdi trung khit vdi cac vach ehia sdn tren thude. Khi dd, khoang van i = 0,1mm.

- Cdn phai do D.

- Ta bd kinh Ipc sac L thi hai ngudn sang S, va Sj la hai ngudn sang trdng, khi dd, ha van giao thoa thu dupe tran man la he van giao thoa cua hai chum sang trdng.

HS chu y quan sat va ldng nghe

GV gidi thieu thiet bi thi nghiem tran

hinh ve 42.2. Yau cdu HS quan sat va

tra ldi cdc eau hdi sau de ndrn dupe

each tien hanh thi nghiem

- Mudn cd anh sang dd dd lam thi

nghiam giao thoa phai lam the nao ?

- Dat mat d trudc hay sau man M dd

quan sat he van giao thoa?

- Thyc ta' trong thi nghiem nay ta co

phai do khoang van giao thoa khdng ?

Ndu khdng ta phai lam gi ?

- Vdy thi nghiam nay ta cdn phai do dai lupng nao ?

- Mudn quan sat hian tupng giao thoa cua hai chum sang trdng ta phai lam thd

nao?

GV gidi thiau phuong an thi nghiem do budc sdng anh sang dd bang bp thi nghiam vdi den laze ban ddn 1 -^5mW.

- Ddi vdi phucmg an thi nghiem nay ngudi ta dimg den laze ban ddn phat ra anh sang dd thay cho viae dung den day tde ndng sang va kinh loc sdc nhu phuong an thi nghipm 1.

- He thdng den laze, bang chfla bai khe

S,, S2, man hflng he van giao thoa dupe

gdn tran gia.

- Can phai do khoang D va khoang vdn i bang thude. Do khoang van i bang

128

each do khoang each cua 6 vah sang hoac 6 van tdi lian tidp, sau dd tinh khoang van i.

Hoat ddng 3 .

Phan nhom, tie'n hanh thi nghiem

Cac nhdm trudng lan nhan thidt bj

thi nghiam vd cho nhdm va nhan

mdu bao cao thi nghiem.

- Sau khi cac nhdm da tien hanh

xong ca hai phuong an thi nghiem

thi lau chui, xdp lai gpn gang cae

dung cu thi nghiem va ban giao lai

cae thia't bj thi nghiem cho GV

GV chia ldp thanh cae 4 nhdm thi nghiam, hai nhdm lam theo phucmg an 1, hai nhdm lam theo phuong an 2. Sau khi lay dupe sd liau, cac nhdm ddi thi nghiem cho nhau dd tia'p tuc lam phucmg an thi nghiem cdn lai.

- Trong qua trinh HS lam thi nghiem, GV di tdi tflng ban thi nghiem dd djnh hudng giup dd HS khi HS gap khd khan.

Hoat ddng 4 .

Xfl li sd lieu va via't bao cao thi

nghiem

HS thao luan nhdm, sau dd ca nhan xfl li sd lieu va via't bao cao.

- Phuang dn I: edn phai tinh:

X='-^ D

. , r fAi Aa AD^ AX = X\ - = - + ^ ^ 4 - ^

V i a D )

vfli A D ^ ^ " ^ ^ " ^ * " ' " - Phuang dn 2 : cdn phai tinh

Yau cdu HS xfl li sd lipu va vidt bao

cao thi nghiem theo mdu cd san trong SGK.

GV yau cdu HS nau each tinh sai sd

trong mdi phuong an thi nghiam va gia

trj eua budc sdng anh sang.

- _ ^1 + ^2 '*' ^ 3

1 _ 1 AX — "*^^ "^'"

GV thu bao cao thi nghiem cua HS sau khi HS da xfl li sd lieu va viet xong bao cao thi nghiam.

TKBG VL#12/2(NC) 129

CHL/ONG VH. Ll/pNG TLf ANH SANG

BAI43

HlfiN TI/CfNG QUANG DI£N NGOAI

cAc DINH LUAT QUANG DifiN

I - M U C T l £ u

1. Vi kie'n thflc

- Hieu va nhd dupe eac khai niem: hian tupng quang dipn, aiectron quang dian, ddng quang didn, gidi ban quang dipn, ddng quang dian bao hoa, hiau dian thd ham.

- Hidu dupe npi dung va nhan xet ka't qua thi nghiam khao sat dinh lupng hian tupng quang dien.

- Hidu va phat tridn dupe edc dinh luat quang dian.

2, Vi ki nSng

- Ren luyan ki nang giai thieh cae hipn tupng vat li. - Ren luyan ki nang phan tich ka't qua thi nghiem.

II - CHUXN BI

Gido vien

- Ve hinh 43.1,43.2,43.3 va 43.4 SGK tran gia'y khd AQ.

Hoc sinh

- 6n lai cac kidn thflc vd cdng eua lye dian trudng, dinh 11 dpng nang, khai niam \ cudng dp ddng dien bao hoa.

130

m - THifiT K£ H O A T D 6 N G D A Y HOC

Hoat ddng cua hoc sinh Trp giup cua giao vi§n

Hoat ddng 1

Kidm tra, chuan bj dieu kien xua't phat. Dat van de HS suy nghl ca nhan tim cau tra ldi

- Khi catdt bi ddt ndng, cae electron ty do trong kim loai nhan dupe nang lupng edn thiet dd bflt ra khdi mat catdt. Do dd, trong dng chan khdng cae electron ty do chuydn dpng hdn loan. Khi khoa K2 ddng, andt dupe ndi vdi cue ducfng, catdt dupe ndi vdi eye am cua ngudn dian thi eac electron se chuyen dpng tfl catdt sang andt tao ra ddng dipn. Khi do sd chi cua miliampe ke khae khdng.

GV nau cau hdi kiem tra kidn thflc cu - Lam thi nghiem vdi didt chan khong theo so dd sau :

Ddt ndng catdt bang ngudn dian î, sau dd md K], ddng K2 thi miliampe kd chi the nao ? Tai sao ?

- Khao sat sy phu thupc cua cudng dp ddng dian trong chan khdng vao hipu dien the U dat gifla andt va catdt ngudi ta thu dupe dudng dac tuydn vdn-ampe

I

O u. u

131

- Cudng dp ddng dian khi dd dat gia tri bao hoa.

Nhan xet gi vd cudng dp ddng dian khi TT V, TT 9 V>U^'7

Hoat ddng 2

Tim hieu hien tupng quang dien ngoai

HS chu y lang nghe va tra ldi eau hdi cua GV

- Do tia tfl ngoai chieu vao tdm kem nan lam cho aiectron bi bat ra khdi ta'm kem. Khi dung tam thuy tinh khdng mau chan chum tia tfl ngoai thi khdng hai la dien nghiem khdng bj khep lai vi ta'm thuy tinh da hdp thu hdu het eac tia tfl ngoai.


GV md ta thi nghiam phat hian hian tupng quang dian do nha vat li ngudi Dfle, Hee da lam, yau cdu HS ldng nghe va tra ldi cac cau hdi dd tim hidu hian tupng quang dien ngoai

t

- Chieu anh s ^ g uu qud7!| vao mpt tdm kem P ban ddu tich dien am thi hai la eua dian nghiem khep lai.

- Chdn chum tia hd quang bang tdm thuy tinh khdng mau thi hai la eua dian nghiem khdng bi khep lai.

Giai thich tai sao ?

GV thong bao - Hian tupng anh sang lam bat eac aiectron ra khdi bd mat kim loai gpi la hian tupng quang dien ngoai, thudng gpi tat la hien tupng quang dien.

- Cac eletron bj bat ra khdi bd mat kim loai bj chieu sang gpi la quang aiectron, hay cdn gpi la aiectron quang dien.

132

Hoat ddng 3

Tim hieu thi nghiam khao sat dinh lupng hien tupng quang dien

HS chu y ldng nghe va quan sat hinh ve te bao quang dian tran gidy khoAo.

- Khi chidu chum sang cd budc sdng ngdn vao catdt thi hien tupng quang dien ngoai xay ra, trong td bao quang dipn xudt hien cac aiectron quang dian. Dudi tac dung ciaa lye dian trudng, cae aiectron

GV gidi thiau te bao quang dien trong thi nghiem khao sat djnh lupng - Td bao quang dien la mpt binh bang thach anh da hut hdt khdng khi, ban trong cd hai dien eye: andt la mpt vdng day kim loai; catdt cd dang mpt chdm cdu bang kim loai ma ta edn khao sat.

GV md ta thi nghiam vdi td bao quang dien, yau cdu HS tra ldi cac cau hdi dd tim hieu thi nghiem khao sat dinh lupng hian tupng quang dipn.

n F

^ • 0

D

O

1 B

P Ml Q

- Ddng khoa C va di chuyen con chay B dd Uî^ >0. Chia'u chum sang cd budc

sdng ngan vao catdt thi hipn tupng gi xay ra ? Nhan xet gi ve sd ehi cua dien kdG?

133

quang dien chuyen dpng tfl catdt sang andt tao thanh ddng dien chay trong mach. Kim dien kd G Ipch khdi vi tri 0.

- Didu kian dd xay ra hien tupng

quang dipn la anh sang chieu tdi

ban kim loai cd budc sdng phai

nhd hon hoac bang mpt gia tri

XQ nao dd.

- Dudng dac tuydn von-ampe khdng phai la dudng thdng nan cudng dp ddng dien trong td bao quang dien khdng tuan theo dinh luat 6m. - Khi U^K > Uj, cudng dp ddng

dian gifl gia tri khdng ddi I = Ibh-

- Khi U^j^ < -Uh thi ddng quang

dian bi triat tiau hoan toan (I = 0).

- Dung cac kinh loc sac F khae nhau

thi thdy ddng quang didn chi xudt hian

khi anh sang chidu vao catdt cd budc

sdng nhd hon hoac bang tri sd XQ.

Vay, didu kian de xay ra hiph tupng

quang dipn la gi ?

- Vdi mpt chum sang don sdc ed budc

sdng X<XQ va cd cudng dp sang nhdt

dinh thi sy phu thupc eua cudng dp

ddng quang dien I vao hieu dian thd

UAK &^^ ^^^^ ^^ ^^^^^ '^^^ ^^ ^^ ^^

dd thi sau:

M.

^bh2

^blil

^ -Vu O u, u

• >

AK

Cudng dp ddng dien cd tuan theo dinh luat 6 m khong ? Khi hiau dien thd UAK ^ ^1 thi cudng dp ddng dien bidn ddi nhu thd nao ? Cudng dp ddng dian cd gia tri bang khdng khi nao ?

134

- Cudng dp ddng I h ti la thuan

vdi cudng do anh sang.

HS t i ^ thu, ghi nhd

Hoat ddng 4

Tim hieu cac dinh luat quang dian

'

- Gifl nguyan tri sd cua budc sdng X,

tang cudng dp sang chieu vao catdt va ve dupe dudng dac tuydn thfl 2. Nhan xet gi vd sy phu thupc cua ddng If,,, vao cudng dp chum sang ?

GV bd sung kidn thflc

- Khi U^K -"^h thi ddng quang dipn

hi triat tiau hoan toan vi: aiectrwi bj bat

ra tfl catdt, vdi tde dp ban ddu VQ ^ ^ va

dpng nang ban ddu, da chiu tac dung eua lye dipn trucmg hudng vd catdt; lye nay da ngan khdng cho aiectron tdi andt dd gay ra ddng quang dian. Vi vay, Uh dupe gpi la hipu dipn thd ham. Tri sd

cua Uf, phu thupc budc sdng X. Nhu

vdy, gifla dpng nang ban ddu cue dai cua aiectron va dp ldn cua hieu dian thd ham cd hp thflc :

xiT ... ^Ômax - pTT "^dmax - 2 ~ '

- Ddng dian I h gpi Id cudng dp ddng

quang dian bao hoa.

GV gidi thiau ba dinh luat quang dien ~ Dinh luat vd gidi han quang dian: Hien tupng quang dian chi xay ra khi anh sang kieh thich chidu vao kim loai cd budc sdng nhd hon hoac bang budc sdng XQ, XQ duac gpi la gidi ban quang

dian cua kim loai dd : XQ< X.

135

HS chu y ldng nghe va ghi nhd


- Dinh luat quang dien thfl nha't dupe rut ra tfl ket qua thi nghiem ddu tian : Didu kian dd xay ra hien tupng quang dian la anh sang chia'u tdi ban kim loai ed budc sdng phai nhd hon hoac bang mpt gia trj XQ nao dd.

- Dya vao dudng dac trung vdn-ampe ta tha'y ddng quang dien bao hoa ti la thuan vdi cudng dp chum sang kich thieh. Ke't qua thi nghiam nay eho phep ta suy ra dinh luat quang dien thfl hai.

- Theo ka't qua thi nghiem tran ta

tha'y: Trj sd cua U,, phu thupc

budc sdng X.

Mat khae W, dmax _" IXOmax _ = eU„

va vdi mdi kim loai thi cd mpt gidi ban quang dien nhat djnh nan ta suy ra dinh luat quang dian thfl 3.

- Dinh luat ve cudng dp ddng quang dien bao hoa : Ddi vdi mdi anh sang thich hpp (cd ô - ^ ) ' cudng dp ddng quang dien bao hoa ti le thuan vdi cudng dp cua chum sang kieh thieh.

- Dinh luat vd dpng nang eye dai cua quang aiectron : Dpng n ^ g ban ddu eye dai eua quang aiectron khong phu thupc vao cudng dp eua chum sang kieh thich, md ehi phu thupc budc sdng anh sang kich thieh va ban ehdt cua kim loai.

GV yau cdu HS tra ldi eau hdi sau de tim hieu eac djnh luat quang dien

- Cac djnh luat quang dipn tran dupe rut ra tfl ket qua thi nghipm nao ?

136

Hoat ddng 5

Cung cd bai hpc va dinh hudng nhiem vu hpc tap tiep theo GV nau cau hdi cung c6 bai hpc

- Hay chflng td ring, ba djnh luat quang dien bao ham dupe tat ca kdt qua thi nghiem tran.

- HS ve nha lam cae bai,tap 1, 2, 3, 4, 5 SGK.

- On lai cac kien thflc da hpe bai 43 SGK va cac khai niam hat, sdng.

137

BAI44

THUYDT LUONG TtT A N H SANG

LUQNG TINH SONG - HAT CUA A N H SANG

I-MUCTlfiU

1. ve' kigh thflc

- Neu dupe npi dung co ban cua gia thuyet lupng tfl cua Piang va thuydt lupng tfl anh sang eua Anh-xtanh.

- Vidt dupe cdng thflc Anh-xtanh vd hian tupng quang dien ngoM.

- Nau dupe anh sang cd ludng tinh sdng-hat.

- van dung dupe thuydt lupng tfl anh sang dd giai thich ba dinh luat quang dian.

2. Ve ki nSng

- Ren luyen ki nang giai thich cac hian tupng vat li.

- Ren luyen ki nang van dung cdng thiic Anh-xtanh vd hian tupng quang dian de giai thieh eac dinh luat quang dien va lam mdt sd bai tap.

~ Ren luyen ki nang suy luan Idgic trong viec dp dung thuydt lupng tfl anh sang dd giai thieh eac djnh luat quang dien.

- Ren luyan ki nang lam bai tap trdc nghiem khach quan nhidu lua chpn vd phdn thuyet lupng tfl anh sang.

II-CHUXNBI

Gido vien

- Chudn bj phia'u hpc tap cho HS.

Hpc sinh

- On lai cae kidn thflc da hpc bai 43 SGK va cac khai niam hat, sdng.

138

m - THifiT K£' HOAT D 6 N G DAY HOC

Hoat ddng cua hoc sinh Trp giup cua giao vi^n

Hoat ddng 1

Kidm tra, chuan bi dieu kien xuat phat. Dat van dd.

HS suy nghl ca nhan tim eau tra ldi - Theo thuyet dipn tfl vd anh sang, cudng dp chum sang kich thich cang ldn, thi dian trudng bidn thian trong anh sang cang manh, lam cho aiectron trorlg kim loai dao dpng cang manh, tde dp va dpng nang cua aiectron cang ldn. Hian tupng quang dipn se xay ra khi dpng nang cua aiectron dat dupe gia trj du ldn de aiectron bflt ra khdi bd mat kim loai. Vay theo thuydt lupng tfl anh sang, mudn hian tupng quang dian xay ra thi cudng dp 6hum sdng kich thich phai ldn hon mpt gidi ban nao dd; draig nang cua aiectron quang dien phu thupc vao cudng dp chum sang kich thich. Ket luan nay mau thudn vdi cac dinh luat quang dien.

GV nau cau hdi kidm tra kien thflc cu - Sfl dung thuydt dian tfl dd giai thi'eh cac dinh ludt quang dian.

Ddt vdn de : Ta da biet, dung thuyet dian tfl vd anh sang khong giai thich dupe cae dinh luat quang dipn. Mudn giai thieh dupe cae dinh ludt quang dian ta edn phai sfl dung mpt tinh chdt khdc eua anh sang ma khdng phai la tinh chdt sdng. vay tinh chat dd la gi? Bai hpe ngay hdm nay giup ehung ta tra ldi eau hdi dd.

139

Hoat ddng 2

Tim hieu thuyet lupng tfl anh sang

HS chu y ldng nghe


GV gidi thiau vd gia thuydt lupng tfl nang lupng cua Plang - Nam 1900, nha vat li ngudi Dfle Plang da dd xudng gia thuydt ve lupng tfl nang lupng nham giai thich sy phat va ha'p thu bfle xa cua cae vat, dac biat la cae vat ndng sang. - Theo Plang thi lupng nang lupng ma mdi lan mpt nguyen tfl hay phan tfl hdp thu hay phat xa cd gia tri hoan toan xac dinh, gpi la lupng tfl nang lupng. Lupng tfl nang lupng, ki hieu la e, cd gia tri

bang: 8 = hf.

Trong dd f la tdn sd eua anh sang bi hdp thu hay dupe phat ra ; h la mpt hang sd, gpi la bang sd Plang, h =

6,625. lO-^'^J.s.

GV gidi thieu npi dung thuyet lupng tfl anh sang - Nam 1905, dd giai thieh dinh luat quang dian, nha bac hpc Anh - xtanh, da phat tridn gia thuyet cua Plang lan mpt budc va dd xudt thuyet lupng tfl anh sang (cdn gpi la thuyet phdtdn). Ndi dung cua thuyet lupng tfl anh sang: 1. Chum anh sang la mdt chum eac phdtdn (cae lupng tfl anh sang). Mdi phdtdn ed nang lupng xa djnh e = hf (f la tdn sd cua sdng anh sang don sac tuong flng). Cudng dp cua chum sang ti la vdi sd phdtdn phat ra trong 1 gidy.

2. Phan tfl, nguyan tfl, aiectron... phat xa hay hdp thu anh sang, cung cd nghia la ehung phat xa hay hdp thu phdtdn.

140

HS lam viec ea nhan tim cau tra ldi

- Ap dung cdng thflc :

e = hf = h -X

6,625.10-^^3.10^

0,75.10 -6 2,65.10-'^:^

- Na'u chum sang la don sdc dd thi cd mpt loai phdtdn flng vdi anh sang dd cd budc sdng X = 0,76|am.

- Neu chum sang mau dd cd eae budc sdng >. = 0,640^ 0,750pm thi cdvosd phdtdn.

3. Cae phdtdn bay dpc theo tia sang vdi

tde dp c = 3.10 m/s trong chan khdng.

GV yau cdu HS tra ldi cac cau hdi sau

de hidu vd thuydt lupng tfl anh sang

- Hay tinh nang lupng cua phcton flng

vdi anh sang dd cd bude sdng

X = 0,15\im.

- Trong chum sang mau dd cd may loai

phdtdn ?

Hoat ddng 3

Ap dung thuyet lupng tiir anh sang de giai thich cac dinh luat quang dien HS thao luan ehung toan ldp

- Nang lupng 8 cung cdp cho aiectron dupe sfl dung dd : eung cdp cho aiectron mpt cdng de nd thoat ra khdi bd mat kim loai, truyen cho nd mpt dpng nang ban ddu va truyen mpt phdn nang lupng cho mang tinh the.

- Khi aiectron ndm ngay tran be mat tinh the.

Ap dung djnh luat bao toan nang lupng, ta cd :

GV nau eau hdi de HS tim hidu cdng thflc Anh - xtanh vd hien tupng quang dian

- Trong hien tupng quang dien, gia sfl electron trong kim loai hdp thu hoan toan photon cua anh sang kich thich. Nang lupng nay dupe dung de lam gi ?

- Khi nao thi aiectron thoat ra khdi bd

mat kim loai va ed dpng nang cue dai?

- Gpi A la cong cdn cung cap cho aiectron d bd mat kim loai, ap dung djnh luat bao toan nang lupng ta ed bidu thflc nhu the nao ?

hf = A + mv Omax

141


- Theo cdng thflc 2

hf = A + ^^^Q"'^. mudn eho hian 2

tupng quang dian xay ra, nghia la mudn eho aiectron bat ra khdi bd mat kim loai dung lam catdt, thi phdtdn cua anh sang chieu vao catdt phai cd nang lupng :

X A ^ he

vay XQ= — chinh la gidi ban

quang dien cua kim loai lam catdt.

- Cudng dp eua ddng quang dian bao hoa ti le thuan vdi sd quang aiectron bdt ra khdi catdt trong mot don vi thdi gian. Vdi cac chum sang cd kha nang gay ra hipn tupng quang dien, thi sd quang aiectron bi bat ra khdi mat catdt trong mpt don vj thdi gian lai ti la thuan vdi sd photon den dap vao mat catdt trong thdi gian dd.

GV thong bao

- Cdng thflc bf = A + ^ ^ ^ ^ la edng

thflc Anh-xtanh vd hien tupng quang dian.

GV nau eau hdi dd HS giai thieh cdc dinh luat quang dien

- Sfl dung thuydt lupng tfl anh sang va edng thflc Anh-xtanh vd hipn tupng quang dien de giai thich ba djnh luat quang dian ?

GV nau cau hdi gpi y - Mudn eho aiectron bat ra khdi bd mat tdm kim loai dung lam eatot thi nang lupng cua phdtdn dnh sang chidu vao cd gia tri nhd nhdt bang bao nhiau ?

- Cudng dp ddng quang dipn bao hod phu thupc nhu thd nao vao sd aiectron quang dian trong mpt don vi thdi gian ?

- Sd aiectron bi bat ra khdi bd mat catdt phu thupc nhu the nao vao cudng dp chum sang kich thich ?

142

Sd phdtdn nay ti la vdi cudng dp eua chum sang tdi. Tfl dd suy ra, cudng dp eua ddng quang dipn bao hod ti le thuan vdi cudng dp eua chum sang chia'u vao catat. - Ta cd :

hf A + "'''Omax 2

_j mv^^g^ _ he ^

2 X

Suy ra dpng nang eye dai ban

ddu phu thupc vao budc sdng ciaa

anh sang kieh thich vd ban chdt

kim loai dung lam catdt.

Hoat ddng 4

Tim hieu luong tinh sdng hat cua

dnh sang


- Ngudi ta sfl dung tinh ehdt sdng

ciia dnh sang de giai thich hian

tupng giao thoa.

- Ngudi ta sfl dung tinh chdt hat cua dnh sang dd giai thich hian tupng quang dian.

- Anh sang ed budc sdng cang ldn,

phdtdn flng vdi nd cd nang lupng

cang ldn. Anh sang thd hipn rd tinh

chdt hat nhu d hian tupng quang

dian. kha nang ddm xuyan ldn, lam

phat quang... NgUpe lai anh sang

cd budc sdng cang dai thi tinh chdt

sdng thd hien cang rd.

- Dya vao cdng thflc Anh-xtanh vd hian tupng quang dien, hay eho biet dpng nang eye dai ban ddu phu thupc vao nhflng yeu td nao ?

GV nau cau hdi dd HS hieu ro ludng tinh sdng hat eua anh sang

- Chung ta da hpc nhflng tinh chat nao cua anh sang ?

- Ngudi ta sfl dung tinh chdt sdng cua anh sang de giai thieh hidn tupng gi da hpc?

- Ngudi ta sfl dung tinh chdt hat cua anh sang dd giai thieh hian tupng gi da hpe ?

- Tinh chat sdng cua dnh sang thd hian rd khi anh sang cd budc sdng nhu thd nao ?

- Tinh chdt hat eua anh sang the hian ro

khi anh sang cd budc sdng nhu the* nao ?

143

Hoat ddng 5


GV the che hoa kidn thflc - Nhu vay, anh sang vfla cd tinh chat sdng, vfla ed tinh ehdt hat. Ngudi ta ndi rang, anh sang ed ludng tinh sdng-hat.

- Trong mdi hien tupng quang hpc, anh sang thudng thd hien ro mpt trong hai tinh cha't tran. Khi tinh eha't sdng thd hien ro, thi tuih ehdt hat lai md nhat, va ngupe lai.

GV yau cdu HS lam bai tap trong phia'u 'hpe tap dd eung cd bai hpc

- HS vd nha lam cae bai tap 4, 5 SGK.

PHIÛ HOC TAP

Cau 1. Chpn cum tfl thich hpp didn vao d trdng

Theo gia thuyet lupng tfl cua Plang thi nang lupng eua ludn bang mpt sd nguyan lan lupng tfl nang lupng.

A. mpi aiectron. B. mpi nguyan tfl.

C. phan tfl eua mpi ehdt. D. mpt chum sang don sdc.

Can 2. Theo thuyet phdtdn eua Anh-xtanh, thi nang lupng

A. ciaa mpi phdtdn ddu bang nhau.

B. eua mpt photon bang mpt lupng tfl nang lupng.

C. giam ddn, khi phdtdn cang rdi xa ngudn.

D. cua photon khdng phu thupc budc sdng.

Cau 3. Cong thflc Anh-xtanh vd hian tupng quang dian la

phai

A. hf = A + mvl

B. hf = A + "IVomax

C. hf ^" '^Q'^^-A. 2

^ he he mv D. ^ + = —— A, A/

144

BAI45

BAI TAP Wt mfiN TUONG QUANG DifiN

l -MUCTl£u /'-:'•'

1. Vi kie'n thflc

- Ndm ehdc va bidt van dung edng thflc Anh-xtanh va eac cong thflc khae ed lian quan den hian tupng quang dian dd giai thich cac bai tap vd hian tUpng quang dien.

2. Ve kl nSng

- Ren luyen ki nang tinh toan bang sd (chuydn ddi don vi, lam trdn sd cd nghia...).

II-CHUXNBI

Gido vien

- Oiudn bi phieu hpe tap cho HS.

Hpc sinh

- 6n tap lai kia'n thflc bai 43 va 44.

Ill - THifiT K£' H O A T D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chu^n bj dieu kien xua't phat

HS suy nghi ea nhan tim cau tra ldi


GV nau cau hdi kidm tra kien thflc cu - Via't cdng thflc Anh-xtanh vd hian tupng quang dian?

- Phat bieu ba djnh luat quang dien.

- Phat bidu thuyet lupng tfl anh sang ciaa Anh-xtanh.

TKBG VLyi2a(NC) 145

Hoat ddng 2

Lam bai tap 1 de biet each van dung cong thflc Anh-xtanh va cac cong thflc cd lien quan vd hien tupng quang dien

HS lam bai tap theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua

a) Ta ed Xn = — " A

Biet h = 6,625.10" "* j.s ; c = 3.10^ m/s

A = 2,15eV= 3,44.10"'^J.

Tfl dd, tinh dupe : XQ « 0,578 pm.

b) Ap dung cdng thflc Anh-xtanh :

— = A+ X

Ômax

"IVomax , t a CO r

m X

Thay sd, ta dupe :

V0max'**3,7.10^m/s.

he c)Tacd:eUh=^^^^^^^= — - A ,

tfldd :Uh = -e X

Thay sd (e = 1,6.10"'^C), ta dupe: Uh= 0,39 V.

d) Nang lupng mdi phdton la:

8 = - = 4 , 0 6 . 1 0 - ' ^ J X

GV yau cdu HS lam bai tap 1 trong phia'u hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua.

GV ndu cac cau hdi gpi y

- Gidi han quang dian cua kim loai dung lam catdt dupe tinh theo edng thflc nao?

- Sfl dung bidu thflc nao dd ed thd xac djnh dupe van tde ban ddu eye dai ciia aiectron quang dien ?

Ne'u y nghia cua hiau dipn thd ham.

- Mudn tinh dupe hiau sudt lupng tfl ta cdn phai xac dinh dupe nhiing dai lupng nao?

146

Sd hat phdtdn tdi catdt mdi giay:

N = — « 3 , 0 8 . 1 0 ' ^ h a t e

Guong dp ddng quang dian bao

hoa l h = ne, vdi n la sd aiectron

bflt ra khdi mat kim loai va chuydn vd andt trong mpt don vj thdi gian. Tfl dd :

n=^ =3,12.10*^ hat e

Hieu sudt lupng tfl :

H = -^«ilO"^=l% N

Hoat ddng 3

Van dung dieu kien xay ra hien tupng quang dian de lam bai tap 2

HS lam bai tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua

Ap dung cdng thflc Anh-xtanh ta ed :

. he 1 2 A=Y--mvo^^

Thay sdtadupe: A=1,94.10"'^L Gidi han quang dian cfla tam kim loai :

A,Q = i ^ = 1,02.10"^ m = 1,02Hm A

Mudn ed hidn tupng quang dien xay ra, budc sdng X eua anh sang kich thich phai thoa man

didu kian X < XQ. DO do :

— 1

•

- Na'u tinh dupe sd quang aiectron bflt ra trong mdt giay va sd phdtdn tdi be mat kim loai trong mpt giay thi cd thd xac djnh dupe hiau sudt lupng tfl khdng ?

- Cdng sudt eua chum sang cd lian he nhu the nao ddi vdi sd phdtdn N eua chum sang chieu tdi be mat kim loai trong I gidy?

- Cucmg dp ddng quang didn bao boa lian ha nhu the nao dd'i vdi sd quang aiectron trong 1 giay ?

GV yau cdu HS lam bai tap 2 trong phia'u hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua.

GV nau eac eau hdi gpi y

- Didu kien de xay ra hien tupng quang dian la gi ?

- Mudn biet hai chum sang chidu tdi i ta'm kim loai cd gay ra hien tupng quang dian hay khong ta cdn phai xae dinh dupe dai lupng nao ?

- Mudn xae djnh dupe gidi ban quang i

dien XQ ta phai xae djnh dupe dai lucmg i

nao ? Sfl dung cdng thflc nao de xac djnh dupe dai lupng dd ?

147

- Vdi X] thi A.] > XQ ndn hien

tupng quang dian khdng xay ra;

- Vdi X2 thi X2<A,Q nan hien

tupng quang dien xay ra. khi dd, dpng nang ban ddu eye dai eua aiectron bdn ra la :

EXom-=]^_A«l,79.10- '«J. 2 X2

Tfldd :voniax ^1.98.10^ m/s.

Hoat ddng 4

Tim hieu khai niem he quy chidu va chuyen dpng tinh tien

HS lam bai tap theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua

a) Gidi ban quang dien eua ddng :

he 6,625.10" '*.3.10^ X{\ — — —

? 4,47.1,6.10 -19

^-6 =«0,278.10"°mft=278nm.

b) Ap dung cdng thflc Anh-xtanh ta cd:

— = A + X

mv Omax

mVomax

Omax

7,044.10"'^J

1,244.10^ m/s.

GV yau cdu HS lam bai tap 3 trong phidu hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua.

GV nau cac cau hdi gpi f

- Tai sao qua cdu tich dien ?

- Dien the cua qua cdu phu thupc nhu the nao vao sd electron bj bat ra khdi b mat qua cdu ?

- Theo thdi gian, didn tich eua qua cdu tang thi dian thd eua qua cdu bien ddi the nao ? Lieu cd thd tang mai khdng ?

- Khi nao dien the cua qua cdu khdng tang nfla ?

- Gia trj dien the eye dai cua qua cdu chinh la dai lupng nao trong te bao quang dian ?

148

Ban ddu, qua cdu chua tich dian. Khi chia'u bfle xa cd budc sdng X vao qua cdu thi aiectron bj bflt ra khdi mat qua cau va qua cdu tich dien duong, qua cdu cd mdt dian the. Sd aiectron bj bflt ra khdi mat qua cdu ngay cang nhidu, dien thd cua qua eau tang ddn va khi dien thd cua qua cdu dat tdi gia trj V ^ thi cac

aiectron vfla mdi blot ra tham lai, lai bj hut trd lai qua cdu, va dian the cua qua cdu khdng tang nfla. vay gia trj eye dai V^ cua dipn the qua cdu chinh la hieu dien the ham trong td bao quang dien. Do dd, ta ed :

eV„=eUK = mvoniax m

Tfl do, suy ra :

e 2

7,044.10 -19 « 4,40 V

1,6.10'

c) Theo tran ta cd :

gy =EXomax_, 6day V^ =3V. m 2

Tfldd:

Ômax 2eV 1,03.10^ m/s.

Ap dung cdng thflc Anh-xtanh :

ll^ = A + ^ ^ ^ = A + eV X 2

m'

- Dya vao cau b ta ed the tinh van tde eye dai ban ddu cua quang aiectron nhu thd nao ?

- Mudn xac dinh budc sdng cua anh

sang kich thieh ta phai ap dung cdng

thflc nao ?

149

suy ra :

^^^ he _ 6,625.10-^^3.10^ A + eV^ (4,47 + 3)1,6.10-'^

mwl66nm.

PHl£u Hpc TAP

cau 1. Chia'u mpt chum anh sang ed budc sdng X = 0,489ta,m lan mpt tdm

kim loai kali dung lam catdt cfla mpt te bao quang dien. Bidt cong thoat aiectron cua kali la 2,l5eV.

a) Tinh gidi ban cua kali.

b) Tinh van tde ban ddu eye dai cua aiectron bdn ra tfl catdt.

c) Tinh hieu dien the ham.

d) Bia't cudng dp ddng quang dien bao hda I h =5mA va cdng sudt cua

chum anh sang chidu vao catdt la S!^=1,25W, hay tinh hiau sudt lupng tfl (ti sd gifla sd aiectron bflt ra khdi mat kim loai va sd phdtdn tdi mat kim loai).

cau 2. Khi chia'u vao mpt tdm kim loai mdt chum sang don sdc cd budc song 0,2}am,dpng nang ban ddu eye dai cua aiectron quang dien la

S.IQ-'^J. Hdi khi chia'u vao tdm tim loai dd ldn lupt hai chum sdng

don sac cd budc sdng Xi=l,40|am va X2 =0,10|am, thi cd xay ra hien

tupng quang dien khong ? Ndu cd, hay xac djnh van tde ban ddu cue dai cua cac aiectron quang dien.

cau 3. Cdng thoat cua aiectron khdi ddng la 4,47eV

a) Tinh gidi han quang dien eua ddng.

b) Khi chia'u bfle xa cd budc sdng ^=^ 0,14pm vao mot qua cdu bdng ddng dat xa cac vdt khae thi qua cdu dupe tich dian den dien thd eye dai la bao nhieu ? Van tde ban ddu eye dai cua aiectron quang didn la bao nhiau ?

c) Chia'u mpt bfle xa didn tfl vao mdt qua cdu bang ddng dat xa cac vat khae thi qua cdu dat dupe dipn the eye dai 3V Hay tinh budc sdng cua bfle xa va van tde ban ddu eye dai cua aiectron quang dipn.

150

BAI46

H I £ N TT/ONG QUANG DifiN TRONG

QUANG DifiN T R 6 VA PIN QUANG DifiN

I-MUCTlfiU

1. va' kie'n thflc

- Dinh nghia dupe hipn tupng quang dian trong.

- van dung de giai thich dupe hien tupng quang ddn.

- Trinh bay dupe djnh nghia, cdu tao cua quang trd va pin quang dipn va hoat ddng cua pin quang dien. - Dy doan dupe vdi cac cudng dp chum sang khae nhau se cho gia tri cudng dp ddng dian khae nhau.

- Dd xudt phucmg an thi nghiam dd kidm tra dupe dy doan : Thay doi cudng dp chum sang dpc gia trj cua cudng-dp ddng dian tuong ihig.

2. va' ki n5ng

- Ren luyan ki nang dua ra dy doan ddi vdi mpt hian tupng vat li.

- Ren kl nang lap mach dian.

- Ren luyen ki nang quan sat, xfl ly thdng tin thu thap dupe:

- Ren luyen kT nang tim hieu cae ung dung ki thuat vat li.

n - C H u X N B I

Gido vien

- Bp thi nghiem bidu didn vd hian tupng quang dian trong va cac flng dung.

- Bp thi nghiem flng dung sfl dung quang trd trong he thdng ddng ngdt den dudng.

- 4 bp thi nghiam khao sat hien tupng quang dipn trong va cac flng dung.

Hpc sinh

- 6n lai cac kia'n thflc vd ddng dien trong chdt ban ddn trong chuong trinh vat li 11 nang cao va eac bai 43 va 44 SGK vat U 12 nang cao.

151

Ill - THlfiT Kfi HOAT © O N G DAY HOC


Hoat ddng 1

Kiem tra, chuan hi dieu kien xuat phat. Dat van de


Hoat ddng 2

Tim hidu hien tupng quang dien trong

HS quan sat GV tidn hanh thi nghiem


GV nau eau hdi kidm tra kia'n thflc cu

- Trinh bay hian tupng quang dian ngoai va giai thieh hipn tupng?

- Phat bidu ba djnh luat quang dian va sfl dung thuydt lupng tfl anh sang ciia Anh-xtanh dd giai thich ba djnh ludt quang dipn.

Dat vdn de : Pin Mat Trdi cung cdp dian nang cho Tram Nghian cihi vu tru qudc td ISS boat dpng dya tren hian tupng nao ? Bai hpc nay giup chflng ta tra ldi cdu hdi dd.

GV tien hanh thi nghiam lam nay sinh vdn dd cdn nghian cihi.

- Lam thi nghiam thdy hipn tupng la khi chidu anh sang vao linh kipn ban dan thi thdy ed ddng trong mach, khi khdng chia'u anh sang vao thi khdng cd ddng trong mach.

- Dung cu dd cd dac tinh la khi chidu sang thi cd ddng chay qua, khi khdng chia'u sang thi khdng cd ddng chay qua. Ngudi ta gpi dung cu nay la quang trd. ~ Trong thyc ta' ed mpt sd chdt ban din nhu: Ge, Si, PbS, PbSe, PbTe, CdS, CdSe, CdTe... cd tinh chat dac bipt nhu vay gpi la tinh quang ddn.

152


- Dieu kian dd cd ddng dien la trong mach phai cd:

+ Dien trudng (Hieu dien tha") + Hat tai (Hat mang dien)

- Trong hai trudng hpp da cd dian trudng, trudng hpp chidu sang da cd hat tai dien thi trong mach mdi cd ddng dien. - Khi chia'u anh sang vao quang trd, mdi phdtdn anh sang kich thieh se truydn toan bp nang lupng eua nd eho mpt electron lian kdt, lam giai phdng khdi mdi Uan kdt dd trd thanh electron din va 16 trdng tham gia vao qua trinh ddn dipn.

HS thao luan ehung toan ldp dua ra dydoan - Na'u tang cudng dp chum sang till cudng dp ddng dian chay trong mach se tang.

- Tang cudng dp chum sang bang each giam khoang each tfl ngudn sang tdi quang trd, do cudng dp ddng dien tuong flng.

Vdn dd cdn nghian cflu : Tai sao khi chia'u anh sang vao quang trd thi quang trd ddn dipn, khi khdng chidu anh sang vao thi quang trd khdng dan dien.

GV nau eac cau hdi gpi y - Didu kian de cd ddng dien la gi ? - Cac em quan sat trong ca hai trudng hpp cd anh sang va khOng cd anh sang chieu vao da cd didu kian nao rdi ? - Sy khae nhau d chieu sang va khdng chia'u sang la gi ? - Liau cd phai anh sang cung cd vai trd gidng nhu hian tupng quang dien ngoai ma ta da biet khdng.

GV nau cau hdi vd vdn dd cdn nghidn cflu tia'p - Ndu gia thuydt tran ma dung thi cudng dp chum sang ed anh hudng dah cudng dp ddng dien trong mach khdng ?

GV nau cdu hdi thidt kd phuong an thi nghiam kiem tra du doan

- Vdi bp thi nghiam vfla tidn hanh lam the nao dd kiem tra didu nay? GV nau cau hdi gpi y

- Cdn phai tien hanh thi nghiem nhu the nao?

- Thay ddi cudng dp chum sang bdng each nao ?

153

HS lam thi nghiem theo nhdm, sau dd dai dien nhdm lan bao cao ket qua

Ket qua thi nghiem : Vdi cae cudng dp chum sang khae nhau se eho mpt gia trj cua cudng dp ddng dien. Tang cudng d6 chum sang chia'u tdi quang trd thi cudng dp ddng dien tang.


- Co thd thay ddi cudng dp chum sang chia'u ldi quang trd bang each thay ddi khoang each tfl ngudn saiig tdi quang trd dupe khdng ?

*^^' yau cdu HS chia ldp thanh 4 nhdm thi nghiam, mac so dd mach dien nhu hinh ve sau vd tien hanh thi nghiem kidm tra

V

GV thdng bao

- Hien tupng tao thanh cac aiectron dan va 16 trdng trong ban dan, do tac dung eua anh sang ed budc sdng thich hpp, gpi la hien tupng quang dien trong.

- Mudn gay dupe hien tupng quang

dien trong thi anh sang kich thich phai

cd bude sdng nhd hon hoac bdng nipt

gia trj ^Q, gpi la gidi han quang dian

ciaa ban ddn.

- Vl nang lupng cdn thidt dd giai phdng

aiectron lian kdt trong ban ddn thudng

nhd hon cdng thoat A cua electron tir

mat kim loai nan gidi ban quang dien

cua nhidu ban ddn nam trong vung anh

sang hdng ngoai. (Thang ban vdi Ge thi

XQ = l,88îm, vdi Si thi XQ=1,1 1pm...

154

- Hien tupng giam dian trd suat, tfle la tang dp ddn dien cua ban ddn, khi cd anh sang chieu vao gpi la hien tupng quang ddn.

Hoat ddng 3

Tim hieu mpt sd ihig dung cua hian tupng quang dian trong

HS chu y ldng nghe va quan sat tran hinh ve.

HS chu y quan sat va lang nghe

GV gidi thieu eau tao cua quang trd da sfl dung lam thi nghiem d tran - Quang trd sfl dung trong thi nghiem tran dupe che tao dua tren hieu img quang dien trong. Dd la mpt tdm ban ddn cd gia tri dien trd thay ddi khi cudng dp chum sang chieu vao nd thay ddi.

- So dd mach dien dung quang trd nhu tran. Ldp ban ddn mdng (2) dupe phu lan dd each dien (1) cd be day chiing 20-^30|am. Tfl hai ddu cua ldp ban ddn,

ngudi ta lam eac dien eye (3) bang kim loai va ddn ra ngoai bang cac day ddn (4). Mach ngoai ndi vdi dien ke (5), mpt dien trd tai va ngudn dien (6).

- Quang trd thudng dupe lap vdi mach khuech dai trong eac thiet bj dieu khidn bang anh sang VD : mach dieu khidn den chidu sang tran dudng, trong cac may do anh sang.

GV tidn hanh thi nghiem ve irng dung quang trd trong he thdng den dudng va giai thich flng dung.

155

r /. lOBOliNCOUflG sit DUNG DUAHnTBCflROHCHEIHfiNtflEHftinlNS ,^

- Ban ngay, khi anh sang chidu vao

quang trd du manh thi dien trd cua nd

r^t nhd so vdiRi- Hiau dipn thd UBE

cung se rdt nhd. Ddng eye bazo Ig

khdng cd va, do dd, ddng cdlecto I -. se

bang khdng. Role khdng boat dpng.

- Ban tdi, khi anh sang chieu vao quang trd yeu ddn mflc nao dd thi dipn trd ciia nd se du ldn. Hipu dipn thd Ugg tang.

Khi Ug£ dat ddn mpt gia tri nao dd thi

xudt hian ddng cue bazo va do dd, xudt

hipn ddng cdlecto I^. Ddng I^ chay

qua role lam cho nd boat dpng va ddng mach thdp sang cac den dudng.

GV gidi diipu ca'u tao va nguyan tde boat dpng eua pin quang dipn, yau cdu HS quan sat so dd ca'u tao

^ y \|/ \^ >y

+

Dien circ trong sudt

-f- Ban din loai p Ban dia loai n Dien circ

156


- Khi anh sang ed budc sdng thich

hpp {X<XQ) chieu vao ldp kim

loai mdng d tran ciang thi anh sang se di xuyan qua ldp nay vao ldp ban ddn loai p, gay ra hien tupng quang dien trong va giai phdng ra eae cap aiectron va 16 trdng. Dien trudng d ldp chuydn tidp p-n ddy Id trdng vd phia ban ddn loai p va ddy aiectron vd phia ban ddn loai n. Do dd, ldp kim loai tran ldp ban ddn loai p se nhidm dian duong va trd thanh dien eye duong cua pin, cdn ldp kim loai dudi ban ddn loai n se nhidm dian am va trd thanh dian cue am.

- ca'u tao cua pin quang dien gdm mpt tdm ban ddn loai n, ban tran cd phu mpt 1 ^ mdng ban ddn loai p. Mat tren cung la mpt ldp kim loai mdng trong sudt vdi anh sang va dudi cung la mpt dd kim loai. Cae ldp kim loai nay ddng vai trd Id cae dian cue.

GV nau cau hdi dd HS tim hidu boat

dpng cua pin quang dian

- Hay cho biet pin quang dien boat

dpng nhu thd nao ?


- Khi cd anh sang thich hpp chidu vao

ldp kim loai trong sudt thi ed hian tupng

gi xay ra ?

- Cac electron va Id trdng se djch

ehuydn nhu the nao ? Tai sao ?

- Dian eye nao ddng vai trd la dian eye

ducfng, dm.

GV thdng bao

- Sudt dien dpng cua mdi pin quang dien thudng cd gia trj tfl 0,5V ddn 0,8V.

- Pin quang dian da trd thanh ngudn cung cdp dian cho cac vung sau, vung

157

Hoat ddng 4

Cling cd bai hpc va dinh hudng

nhiem vu hpc tap tie'p theo

HS suy nghl ca nhan tim eau tra ldi

xa d nude ta, tran cae va tinh nhan tao, eon tau vu try, trong eae may do anh sang, may tinh bd tui...

GV nau eau hdi cung cd kidn thflc

- Tai sao tia hdng ngoai chi cd thd gay ra dupe hian tupng quang dien trong, cdn tia tfl ngoai mdi gay ra dupe hian tupng quang dian ngoai ?

- HS ve nha lam cac bai tap 1,2,3 SGK.

- On lai thuyat lupng tu anh sang va kia'n thflc vd cdu tao nguyan tfl trong mon hoa hpe.

158

BAI47

MAu NGUYfiN TLT BO vA QUANG P H 6 VACH

CUA NGUYfiN TLT H I D R O

I-MUCTI£U

1. va' kien thflc

- Phat bidu dupe eac tian dd cua Bo.

- Md ta dupe cae day quang phd vach cua nguyan tfl hidrd va nau dupe co che tao thanh cac day quang phd vach phat xa va hap thu cua nguyan tfl nay.

- Giai dupe eae bai tap vd tinh bude sdng cac vach quang phd eua nguyan tfl hidrd.

2. Va' ki ning

- Ren luyan ki nang giai thich sy tao thanh quang phd vach cua nguyan tfl hidrd. - Ren luyen kT nang thu thap thdng tin khi dpc tai lieu. - Ren luyen ki nang lam eac bai tap trdc nghiam khach quan nhidu lya chpn phdn mdu nguyan tfl Bo va quang phd vach cua nguyan tfl hidrd.

II-CHUXNBI

Gido vien

- Ve hinh 47.3 va 47.4 SGK tran cung mpt td gia'y khd AQ.

- Chuan bi phieu hpe tap.

Hpc sinh

- On lai thuyet lupng tfl anh sang va ve cdu tao nguyan tfl trong mon hoa hpc.



Hoat ddng 1

Kiem tra, chuan bi dieu kien xuat phat. Dat van de HS suy nghl ea nhan tim cau tra ldi



- Phat bieu thuyet lupng tfl cua Anh-xtanh.

159

HS nhan thflc dupe van de eua bai hoc

Ddt vdn de : Bai 39 chflng ta da bidt. quang phd vach phat xa cua nguyan tu hidrO. Giai thich sy tao thanh quang phd nay nhu thd nao. Bai hoc ngay horn nay giup chflng ta tra ldi cau hdi dd.

Hoat ddng 2

Tim hieu cac tien de cua Bo

HS lam viec ca nhan

- Nguydn tfl chi tdn tai trong

mpt sd trang thai cd nang lupng

xac dinh E^, gpi la cac trang

thai dflng. Khi d trang thai dflng, nguyan tfl khdng bfle xa.

- Trang thai dflng la trang thai cd

nang lupng xac djnh.

- Trang thai dflng cd nang lupng thap nha't gpi la trang thai co ban. Cac trang thai dimg cd nang lupng cao hon gpi la trang thai kich thieh. ,

- Thdi gian sdng tmng binh eua eac nguyan tfl trong cae trang thai kich

thich rdt ngdn (chi cd 10"^s). Sau dd nguyan tfl chuydn ve cae trang thai dflng cd nang lupng thdp hon, va cudi ciing vd trang thai co ban.

- O trang thai dflng, ban kinh quy dao chuyen dpng cua aiectron hoan toan xae djnh. Cac quy dao chuyen dpng cua aiectron khi nguyan tfl d trang thai dflng gpi la quy dao dimg.

GV yau cdu HS dpc mue 1 SGK dd tim hidu eae tian dd cua Bo, sau do tra ldi cae eau hdi sau day kidm tra sy thu thap thdng tin khi dpc SGK

- Npi dung tian de vd trang thai dflng.

- Trang thai dflng la trang thai nhu thd

nao?

- Trang thai dflng cd nang lupng thdp

nhat gpi la gi ? Cac trang thai edn lai

gpi la gi ?

- Nhan xet gi vd thdi gian sdng trung binh cua cae nguyan tfl trong eac trang thai kieh thieh.

- Xu hudng sdng eua cac nguyan tfl d trang thai nao.

- Ci trang thai dimg, ban kinh quy dao

chuydn dpng cua aiectron ed dac diem

160

- Quy dao diing cua aiectron trong

nguyan tfl hidrd : r„ = n \ trong dd

n la sd nguyan va n = 1, 2, 3,... tuong flng vdi tan eac quy dao diJmg

K,L,M ro-5 ,3 .10""m goi la

ban kinh Bo.

- Khi nguyen tfl chuydn tfl trang

thai di^g cd ndng lupng E^

sang trang thai dflng cd nang

lupng E ^ nhd hon thi nguyan tfl

phat ra mpt phdtdn cd nang

lupng dung bang hiau E , -Ej^-

- Ngupe lai, ndu nguyan tfl dang

d trang thai dflng cd nang lupng

E i ma ha'p thu dupe mpt photon

cd nang lupng hf dung bang hieu

En -E^^ thi nd chuyen sang

trang thai dimg cd nang lupng

Ej, ldn hon.

- Theo tian de vd sy bfle xa va hdp thu nang lupng eua nguyan tfl, mudn nguyan tfl d trang thai co ban chuyen sang trang thai kich thich thi nguyen tfl phai hdp thu mpt phdtdn cd nang lupng dung bang hiau hai mflc nang lupng tran.

- Mudn nguyan tfl dang d trang thai kich thich mudn chuyen vd trang thdi kich thich ed nang lupng nhd hon thi nguyan tfl phai phat xa

- Nau cdng thflc tinh ban kinh quy dao dflng ciaa aiectron trong nguyan tfl hidro va giai thich y nghia cac dai lupng trong cong thflc dd ?

- N p i dung tien dd vd sy bfle xa va hdp

thu nang lupng ciaa nguyan tfl.

- Khi nguydn tfl dang d trang thai ca

ban mudn ehuydn sang trang thai kich

thich thi nguyan tfl phai the nao ?

- Khi nguyan tfl dang d trang thai kich thich mudn chuyen vd trang thai kich thich cd nang lupng nhd hon phai the nao?

TKBGVL:?12/2(NC). 161

mpt phdtdn anh sdng cd nang lupng bang hiau hai mflc nang lupng tran.

HS quan sat va ehu y ldng nghe

GV thdng bao

- Sy chuydn mflc nang lupng khi hdp thu va khi phat xa phdtdn dupe bidu didn qua so dd sau :

'm Hoat ddng 3

Giai thich su tao thanh quang phd vach ciia nguyen tfl hidrd HS quan sat hinh ve va thao ludn

ehung toan ldp

- Khi aiectron d cdc quy dao dflng K, L, M, N... thi nguyan tfl hidrd d cae trang thai dimg cd mflc nang lupng tuong flng la E|, E2, E3,

E4...

- Mflc nang lupng th^p nhdt la E,,

khi nguyan tfl hidrd d trang thai cd mflc nang lupng nay thi aiectron chuyen dpng tran quy dao dflng K.

- Khi chup anh quang phd cua nguyan tu hidrd ngudi ta thu dupe ba day quang phd: Lai-man, Ban-me. Pa-sen.

GV yeu cdu HS quan sat hai hinh 47.3 va 47.4 dupe ve tran cung mpt khd gidy AQ, sau dd tra ldi cac cdu hdi sau dd giai thich sy tao thanh quang phd vach ciia nguyan tfl hidrd

- Quan sat tran hinh ve hay cho bidt: khi aiectron d cdc quy dao dflng K, L, M, N... thi nguyan tit hidrd d cae trang thdi dflng ed mflc nang lupng tucmg flng

nao .'

- Mflc nang lupng ndo Id thafp nhdt, khi nguyan tfl hidrd d trang thai diJmg c6 mflc nang luong thdp nhdt thi aiectron chuydn dpng d quy dao nao ?

- Nhin vao hinh ve, hay cho bidt khi chup anh quang phd cua nguyan tfl hidrd ngudi ta thu dupe may day quang phd ? Kd tan eae day quang phd ?

162

- Day Lai-man dupe tao thanh khi aiectron chuydn tfl eac quy dao dimg ban ngoai ve quy dao K: L ^ K; M ^ K ; N ^ K... Day Ban - me dupe tao thanh khi aiectron tfl eac quy dao ngoai vd quy dao L : M -> L ; N ^ L; 0 -> L; P -> L... Day Pa-sen dupe tao thanh khi aiectron chuyen tfl cdc quy dao ben ngoai ve quy daoM.

- Bdn vach quang phd dd H^ ,

lam Hp, cham H.^, tim Hg thupc

day quang phd Ban-me. Cac vach dd dupe tao thanh khi aiectron chuydn tfl quy dao M, N, 0 , P vd quy dao L.

Hoat ddng 4



- Hay ndi ro sU ehuydn cac mflc nang lupng cua nguyan tfl hidrd va sy chuyen quy dao dflng tuong flng vdi cac mflc nang lupng cua aiectron trong cac day quang phd dd ?

- Bdn vach quang phd dd H^ , lam Hp,

.cham H^, tim Hg thupc day quang phd

nao ? Tuong flng vdi cae vach dd thi aiectron chuydn tfl quy dao ban ngoai nao vd quy dao nao ?

GV yau cdu HS lam cae bai tap trac nghiam trong phieu hpc tdp de cung ed bai hpc

- HS vd nha lam bai tap 4 SGK.

- On lai cac kidn thflc ve quang phd hdp

thu.

PHlfiu HOC T^P

cau 1. Trang thai dflng cua mpt nguyan tu la

A. trang thai dung yan cua nguyan tfl.

B. trang thai chuyen dpng ddu cua nguyan tfl.

C. trang thai trong dd mpi aiectron ciaa nguyan tfl deu khong chuyen dpng ddi vdi hat nhan.

D. mpt trong sd eac trang thai cd nang lupng xac djnh, ma nguyan tfl dd cd thd tdn tai.

163

cau 2. d trang thai diing, nguyan tfl

A. khdng bfle xa va khong hdp thu nang lupng.

B. khdng bfle xa, nhung ed the hap thu nang lupng.

C. khdng ha'p thu, nhung cd thd bfle xa nang lupng.

D. vdn ed the hap thu va bfle xa nang lucmg.

cau 3, Day Ban-me ihig vdi sy chuyen aiectron tfl quy dao d xa hat nhan vd quy dao nao trong cac quy dao sau day ?

A. Quy dao K.

B. Quy dao L.

C. Quy dao M.

D. Quy dao N.

164

BAI48

HAP THU VA PHAN XA LOG LiTA ANH SANG

MAUSACCACVAT

I - M U C T l £ u

1. Ve ki^n thuTc

-Hidu dupe hien tupng hap thu anh sang la gi va phat bidu dupe dinh luat hdp thu anh sang

- Hieu dupe sy phan xa loc lya la gi ?

- Giai thich dupe tai sao cac vat cd mau sdc khae nhau.

2. va" ki nang

- Ren luyen kl nang giai thich cac hian tupng vat li. - Ren luyen kl nang lam cac bai tap trdc nghiem khach quan nhidu lya chpn phdn hdp thu va phan xa Ipc lya anh sang.

II-CHUXNBI

Gido vien

- Mpt sd ta'm kinh mau.

- Chudn bj phieu hpc tap cho HS.

Hpc sinh

- On lai cac kien thflc vd quang phd hap thu.



Hoat ddng 1

Kiem tra, chuan bi dieu kien xuat phat. Dat van de



GV nau cau hoi kidm tra kien thflc cu - Quang phd vach hdt thu cd the thu dupe trong didu kien nao ? Nau dac didm cua quang phd vach ha'p thu.

165

HS nhan thflc dupe vdn dd eua bai hoe

Ddt vdn de : Dudi anh sang trdng cua bdng den day tde ta quan sat thdy eae vat CO cac mau sac khdc nhau. Tai sao lai nhu vay ? Bai hpc ngay hdm nay giup ta tra ldi eau hdi dd.

Hoat ddng 2

Tim hidu su h^p thu anh sang



- Tdm thuy tinh se ndng lan do ha'p thu quang nang cua chum sang chia'u tdi.

- Cudng dp chum sang thu dupe

K I Q .


GV thdng bao

- Cudng dp cua mpt chum sang dupe xae dinh bang lupng quan nang va chum sang tai qua mpt don vi dien tich dat vudng gde vdi tia sang trong mpt giay.

- Don vj cua cudng dp sang la oat tran

met vudng (W/m ).

GV nau cau hdi dd HS tim hieu sy hdp thu anh sang.

- Chia'u chum sang qua mpt tdm thuy tinh mau dd (vi du nhu den pin) khoang 10 phut, sd tay vao ta'm thuy tinh thi thdy hian tupng gi ? Giai thich tai sao ? Nhan xet gi vd cudng dp chum sang I thu dupe sau khi qua tdm thuy tinh va cudng dp chum sang IQ trudc khi chieu qua ta'm thuy tinh?

GV thdng bao

- Ha'p thu anh sang la hien tupng mdi trudng vat chdt lam giam cudng d6 eua chum sang truyen qua nd.

- Viec khao sat djnh lupng sy hdp thu anh sang cho thdy: Cudng d6 I ciia chum sang don sdc khi truyen qua mdi trudng hdp thu, giam theo dinh luat ham mu cua dp dai d cua dudng

di tia sang : I=Ioe""''.

166

HS thao luan ehung toan ldp - Ta quan sat dupe bd'n vach quang phd ha'p thu Id nhflng vach tdi tai dflng cac vi tri vach dd H^, lam

Hp, chdm Uy, tim Hg tran ndn

quang phd lien tuc.


•;vv/-^ .•;..

•'•••'• " " ^ '

vdi IQ Id cudng dp cua chum sang tdi mdi trudng, a dupe gpi la ha sd hdp thu ciaa mdi trudng. Dd chinh la npi dung djnh luat vd sy ha'p thu anh sang

GV nau eau hdi dd HS tim hidu sy ha'p thu loc lya.

- Khi cho chflm sdng trang qua dng thuy tinh cd khi hidrd nung ndng vao may quang phd thi ta thu dupe quang phd nhu thd nao ?

i-'-U

'••Vi5 GV thdng bao - Didu dd chflng td cac anh sang ed budc sdng khae nhau thi bi mdi trudng ha'p thy nhidu, it khae nhau. Ndi each khae, sy hd p thu anh sang eua mpt mdi trudng cd tinh chpn loc, ha sd hdp thy cua mdi trudng phu thude vao bude sdng anh sang.

- Mpi chdt ddu hdp thu ed chpn Ipc anh sang. Nhung ehdt hdu nhu khdng hdp thu anh sang trong midn nao cua quang phd dupe gpi la gdn trong sudt vdi midn quang phd dd.

- Nhflng vai khdng hdp thu anh sang trong mien nhin tha'y cua quang phd dupe gpi la vat trong sudt khdng mau (chang han nhu nude nguyan ehdt, khdng khi, thuy tinh khdng mau...). Nhflng vat ha'p thu hoan toan vdi anh sang nhin tha'y thi cd mau den.

167

Hoat ddng 3

Tim hieu sy phan xa hoac tan xa

loc lua va mau sac cac vat


- Mudn nhin thdy cac vat thi anh truyen tdi vat phai phan xa hoac tan xa tdi mdt ngudi quan sat.

- Khi nhin thdy vat mau dd chflng td vat phan xa hoac tan xa anh sang dd tdi mat va hap thu hdu bet cac anh sang cdn lai.

- Khi khdng cd anh sang mau nao truydn tdi mdt thi quan sat tha'y vat cd mau den.


- Nhung vat hdp thu loc lya anh sang trong midn nhin thay thi dupe gpi la vat trong sudt cd mau.

GV nau cau hdi de HS tim hidu sy phan xa hoac tan xa va mau sdc cac vat

- Tai sao ehung ta lai nhin thdy cac vat cd mau sdc khae nhau khi chflng dupe chidu sang bdi cung mpt ngudn sang trdng ?

GV nau eau hdi gpi y

- Mudn nhin tha'y cac vat thi anh sang phai dupe truyen nhu tha' nao?

- Nhin tha'y vat mau dd chflng td anh sang mau nao dupe truyen tdi mat?

- Khi khdng ed anh sang mau nao truydn tdi mdt thi ta quan sat thdy vat mau gi ?

GV thong bao

- Mpt sd vat, kha nang phan xa (hoac tan xa) anh sang manh, ydu khae nhau phu thupc vao budc sdng anh sang tdi. Cd nhiing vat phan xa (hoac tan xa) manh cae anh sang cd bude sdng dai, nhung phan xa (hoac tan xa) yeu cae anh sang cd bude sdng ngan. Dd la sU phan xa cd loc lya.

- Khi chieu mpt chum sang trdng vao mpt vat, thi do vat ed kha nang phan xa (hoac tan xa) loc lya, nen anh sang phan xa (hoac tan xa) la anh sang mau. Didu dd giai thich lai sao cac vat ed mau sdc khae nhau.

168

Hoat ddng 4

Cung cd bai hpc va dinh hudng nhiem vu hpc tap tia'p theo

- Cac vat the khae nhau cd mau sdc khae nhau la do ehung dupe eau tao tfl nhihig vat lieu khae nhau. Khi ta chidu anh sang trdng vao vat, vat hdp thu mpt sd anh sang don sdc va phan xa, tan xa, hoac cho truyen qua cac anh sang don sdc khae.

GV yeu cau HS lam eac bai tap trong

phia'u hpc tap dd cung cd kien thflc

- HS on tap cac kien thflc bai 45.

PHlfiu HOC TAP

cau 1. Cudng dp cua chum sang don sdc truydn qua moi trudng hap thy

A. giam ti le vdi dp dai dudng di cua ti^ sang.

B. giam ti le vdi binh phuong dp dai dudng di cua tia sang.

C. giam theo djnh luat ham mu cua dp dai dudng di ciaa tia sang.

D. giam theo ti le nghjch vdi dp dai dudng di cfla tia sang.

Cau 2. Khi chieu vao tam bia dd chiim sang tim, ta thay tam bia cd mau

A. tim. B. dd.

C. vang. D. den.

169

BAI49

Sir PHAT QUANG. SO LUdc vt LAZE

I-MUCTlfiU

l.V§'ki^n thflc

- Hidu hian tupng quang - phat quang.

- Phan biat dupe huynh quang va ldn quang.

- Phat bidu dupe dinh luat Stdc vd phat quang.

- Hieu duoc laze la gi va mpt sd flng dung eua tia laze,

2. va' ki nSng

- Ren luyen kl nang thu thap thdng tin khi dpc tai liau.

- Ren luyen ki nang tim hidu cac flng dung kT thuat vat li.

II-CHUXNBI

Gido vien

- But laze.

- But thfl tidn.

- Laze khi dung trong trudng hpc (ndu ed).

Hpc sinh

- On lai cac kidn thflc vd quang phd hdp thu va quang phd phat xa.

Ill - THlfiT K £ H O A T D O N G DAY HOC


Hoat ddng 1

Kiem tra, chuan bi dieu kien xuat phat. Dat van de


Trp giup cua giao viSn

GV nau cau hdi kidm tra kidn thflc cu - Hian tupng hdp thu anh sang la gi ? Hiat bidu djnh luat ha'p thu anh sang?

170

HS nhan thflc dupe vim dd eua bai hpc

Hoat dong 2

Tim hidu hien tupng phat quang

HS lam viec ca nhan, sau dd thao luan ehung toan ldp.

- Hai dac didm khae biat quang trpng gifla hien tupng phat quang va sy phat sang thong thudng la: + Mdt la, bfle xa phat quang la bfle xa riang cua mdi vat : mdi ehdt phat quang cd mpt quang phd dac trung cho nd.

- Nung ndng mpt cue sdt, d nhiat dp nao thi cue sdt bat ddu phat bfle xa nhin thdy ? Khi nao thi quang phd cua nd la quang phd lian tuc.

Ddt vdn de : Cue sdt dupe nung ndng phat ra cae bfle xa nhin thdy, dom ddm phat ra bfle xa nhin thdy hoac mpt sd eha't hoi, eha't rdn khi dupe chieu sang bang tia tfl ngoai eung phat ra bfle xa nhin thdy. Tdt ca eac trudng hpp nhu vdy ddu dupe gpi la sy phat sang. Tuy nhian, trong dd cd mpt sd trudng hpp gpi la sy phat quang. Sy phat quang ed nhflng dac diem khae biet vdi cac hien tupng phat sang khae. Bai hpc ngay hdm nay ehung ta di tim hidu dieu dd.

GV thong bao vd sy phat quang - Sy phat quang la mpt dang phat anh sang rat phd bien trong ty nhian. Cd mpt sd chdt (d thd rdn, long hoac khO khi hdp thu nang lupng dudi mpt dang nao dd, thi ed kha nang phat ra eac bfle xa dien tfl trong mien anh sang nhin thdy. Cac hian tupng dd gpi la sy phat quang. GV yau cdu HS dpc SGK de tim hidu diem khae biet gifla sy phat quang vdi cae hian tupng phat sang khae.

171

+ Hai la, sau khi ngflng kich thich, sy phat quang ciaa mpt sd chdt cdn tiep tuc keo dai tham mpt khoang thdi gian nao dd, rdi mdi ngiing ban. Khoang thdi gian tfl luc ngflng kich thich cho den luc ngimg phat quang gpi la thdi gian phat quang. Tuy theo chat phat quang ma thdi gian phat quang ed thd keo dai tfl

10~ s cho den vai ngay.


- Sy phat quang cua cac cong tie

dien trong gia dinh.

- Sy phat quang cua cac bidn bao

giao thong.

- Su phat quang cua cac chdt chfla

trong cae ddng tidn Viat Nam.

HS lam viae ca nhan, sau dd thao

luan ehung toan ldp

- Huynh quang va lan quang ddu

la sy phat quang. Tuy nhien hai

hien tupng nay khae nhau d thdi

gian phat quang.

- Huynh quang la sy phat quang

ed thdi gian phat quang ngdn dudi

lO-'Os.

- Lan quang la sy phat quang cd

thdi gian phat quang dai.

GV yau cau HS ldy vi du ve sy phat

quang trong ddi sdng

GV yau cdu HS tidp tuc dpc SGK va cho

bidt sy gidng va khae nhau gifla huynh

quang va lan quang.

GV thong bao dinh luat Xtde vd sy phat quang va cae flng dung cua hien tupng phat quang.

172

HS tidp thu, ghi nhd - Anh sang phat quang ed bude sdng X'

dai hon budc sdng cua anh sang kieh

thieh X: X' >X.

- Cac loai hien tupng phat quang cd rat nhidu flng dung trong khoa hpc, kT thuat va ddi sdng, nhu su dung trong eac den dng dd thap sang, trong cac man hinh cua dao dpng ki dien tfl, cua ti vi, may tinh, sfl dung son phat quang quet tran cac bien bao giao thdng.

Hoat ddng 3

Tim hieu ve laze va cac flng

dung


- Laze sfl dung trong but laze, trong y hoc, trong cae den san khdu...

- Laze cd tinh don sdc, la mpt chiim sang song song va cd cudng do ldn

HS lam viae ca nhan

- Tia laze cd uu the dac biat trong thdng tin lian lac vo tuyen (nhu truyen thdng tin bang ap quang, vo tuyen djnh vi, didu khien con tau vu tru...).

- Tia laze dupe dung nhu dao md trong phdu thuat mat, dd chfla mpt sd banh ngoai da (nhd tac dung nhiet)...

- Tia laze dupe dung trong cac ddu doc dia CD, but trd bang...

GV nau eau hdi dd HS tim hidu, tinh chat ciaa laze.

- Hay ke mdt sd laze ma em da biet trong ddi sdng ? Cho bidt eac tinh chat cua laze ?

GV bd sung kien thflc

- Tia laze la chum sang ket hpp.

Gv yeu cau HS dpc SGK de tim hidu

mpt sd flng dung eua tia laze

173

- Ngoai ra, tia laze edn dupe dung dd khoan, cdt, tdi,... ehinh xae eac vat lieu trong cdng nghiap.

Hoat ddng 4

Tim hieu hien tupng phat xa cam flng

HS doe SGK, sau dd nghe eau hdi cua GV va thao luain ehung toan ldp de tim cau tra ldi.

- Dieu kien cdn : nguyan tfl d trong trang thai kich thich, sdn sang phat ra mpt photon ed nang lupng 8 = hf.

- Dieu kien du : cd mpt photon cd nang lupng bang hf bay ludt qua nd.

- Sd photon phat ra trong Men tupng phat xa cam flng tang theo cdp sd nhan.

- Cac photon ed eiing nang lupng nan sdng dian tfl tuong flng ed eung budc sdng, vi vay laze cd tinh don sdc cao.

- Cac photon bay theo cung mdt phuong nan ehung ed tinh dinh hudng cao. Vi sd lupng photon ldn nan chflng cd cudng dp ra't ldn.

- Sdng dian tfl flng vdi cac photon dao dpng ciing pha va trong cflng mdt mat phang song song vdi mat phung dao dpng ciaa sdng dian tfl img vdi photon s' nen chflng cd tinh chat ka't hpp.

GV yau cdu HS dpc bai dpc tham -SGK sau dd tra ldi cau hdi dd tim hidu vd hien tupng phat xa cam flng.

- Dieu kien cdn va du dd xay ra hian tupng phat xa cam flng.

- Liau rdng nguyan tfl dang d trang thai CO ban cd xay ra hipn tupng phat xa cam flng dupe khong.

- Nhan xet gi vd sd photon phat ra trong hian tupng phat xa cam flng.

- Photon do nguyan tfl phat ra va photon bay ludt qua nd cd dac didm gi ? Tfl dd suy ra tinh chat cua laze ?

174

• • — — ^


Hoat ddng 5

Cung cd bai hpc va djnh hudng nhiem vu hpc tap tie'p theo

HS lam viae ea nhan tim cau tra ldi

GV thdng bao - vay, ed thd ndi : Laze la mpt ngudn sang phat ra mpt chum sang cudng dd ldn dya tran vipc flng dung hian tupng phat xa cam flng.

GV nau eau hdi ciang cd bai hpc

- Nau mpt sd vi du vd hien tupng phdt quang. Phan biet lan quang va huynh quang. - HS vd nha lam cae bai tap 1, 2 SGK.

175

CHWONG Vlll. SO Ll /pC VE THUYET Tl/ONG DOI HEP

BAI50

THUYDT TLfONG D 6 I HEP

I-MUCTlfiU

1. Va' kia'n thflc

- Hidu dupe ban che cua eo hpc cd didn. - Hidu va phat bidu dupe hai tieu dd cua thuydt tuong ddi hep. - Neu dupe ha qua eua thuyet tuong ddi vd tinh tuong ddi cua khdng gian vd thdi gian, van dung cac he qua eiia thuydt tuong ddi tinh dd lam eac bai tap trac nghiem khach quan nhidu lya chon.

2. Vi ki nSng

- Ren luyen ki nang giai thich cae hian tupng vat li. - Ren luypn ki nang thu thap thdng tin khi dpc tai lieu. - Ren luyen ki nang lam cae bai tap trdc nghiem khach quan nhidu lya chpn vd thuyet tuong ddi hep.

II - CHUXN BI

Gido vien


Hpc sinh

- On lai cac kien thflc vd tinh tuong ddi cua chuydn dpng da hpe trong Ca hpc.

Ill - THifiT Kfi' HOAT D 6 N G DAY HOC


Hoat ddng 1 Kidm tra, chuan hi dieu kien xua't phat HS suy nghl ca nhan tim cau tra ldi

Trp giiip cua giao vidn

GV nau cau hdi kidm tra kien thflc cu - Viet cong thflc cpng van tde va trinh bay y nghia cae dai lupng trong edng thflc ?

176

Hoat ddng 2

Tim hidu ban ehd cua co hpc cd

dien


Ddt vdn de : Hanh khdeh ngdi trong mpt con tau (do Anh-xtanh gia tudng), ehuydn ddng vdi tde dp 240000 km/s chay qua san ga, thdy chidu dai sdn ga CO ngan lai. Trong khi dd, quan sat vian dflng yan tran san ga thdy chidu dai con tau CO ngan lai. Cd dung nhu vay khong ? Bai hpc ngay hdm nay giup ehung ta tra ldi cau hdi dd.

GV thdng bao han ehd eua cO hpc co

didn

- Co hpe cd dien (cdn dupe gpi la eo hpc Niu-ton, do Niu-ton xay dyng), da ehidm mpt vj tri quan trpng trong su phat tridn cua vat li hpc cd didn va dupe ap dung rpng rai trong khoa hpe la thuat.

- Nhung den cudi thd ki XIX ddu the ki XX, khoa hpc ki thuat phat tridn rdt manh, trong nhflng trudng hpp vat chuydn dpng vdi tde dp xdp xi bang tde dp anh sang thi co hpe Niu-ton khong edn dung nfla. Chang ban, thi nghiam cho tha'y tde dp c eua anh sang truydn trong chan

. khdng luon cd gia tri c = 3CX)(XK)0 km/s khdng phu thupc vao ngudn sang dflng yan hay chuydn dpng. Hon nfla, tde dp cua cac hat khdng thd vupt qua tri sd e = 3000000 km/s.

- Nam 1905, Anh-xtanh da xay dyng mpt Ii thuyet tdng quat hon co hpc Niu- ton gpi la thuydt tuong ddi hep Anh-xtanh.

TKBGVL^12/2(NC) 177

Hoat ddng 3

Tim hieu cac tien de Anh- xtanh va cac he qua

HS lam viae ea nhan

- TiSn de I : Cae dinh ludt vdt li (co hpc, dian tfl h p c . ) ed cung mpt dang nhu nhau trong mpt hp quy chia'u quan tinh.

- Tien de II : Tde dp eua anh sang trong chan khdng ed eung dp ldn bang e trong mpi he quy chia'u quan tinh, khdng phu thupc vao phuong truydn va tde dp eua ngudn sang hay may thu :

c = 299792458m/s ^ 300 000 km/s.

HS lam viae ea nhan, sau dd thao luan ehung toan ldp

trong dd, / la dp dai cua thanh

khi thanh dung yan, gpi la dp dai riang; V la tde ehuydn dpng eua thanh dpc theo true toa dp cua he K.

- Chieu dai eua thanh bi co lai theo phuong ehuydn dpng theo ti le :

- Khai niem khdng gian la tuong ddi, phu thupc vao he quy chidu quan tinh.

GV yau cdu HS dpc mue 2 SGK va trinh bay npi dung hai tian dd Anh-xtanh

GV yau cdu HS dpc mue 3 SGK va tra ldi cac cdu hdi sau dd tim hidu cac ha qua cua tian dd Anh-xtanh

- Viet cdng thflc xac djnh dp dai / ciia mpt thanh chuydn dpng dpc theo true tea dp eua mdt hp quy chieu quan tinh K? Trinh bay y nghia eae dai "lupng trong edng thflc ?

- Hay cho biet ngucri quan sat dung trong ha quy chieu K thdy chidu dai thanh thay ddi nhu thd nao ?

- Khai niem khong gian la tuong ddi hay tuyet ddi ? Nd cd phu thupc vao he quy chia'u quan tinh khdng ?

178

M - ^'o

Ato ^ khoang thdi gian xay ra hien

tupng theo ddng hd gan vdi he quy

chidu chuyen dpng K'; At la

khoang thdi gian xdy ra hian tupng

theo ddng hd gdn vdi ha quy chidu

dflng yan ; v la tde dp cua he quy

chia'u quan tinh K' dd'i vdi ha quy

chidu quan tinh K.

- Thdi gian ed tinh tuong ddi, phu thupc vao ha quy chieu quan tinh.

Hoat ddng 5

Cling cd bai hpc va djnh hudng

nhiem vu hpc tap tiep theo

HS lam viec ca nhan, sau dd thao luan ehung toan ldp

- Vidt edng thflc xae djnh khoang thdi gian xay ra mpt hien tupng trong ha quy chia'u chuydn dpng K' do ngudi quan sat dung yan trong ha K do dupe ? Nau y nghia cac dai lupng trong edng thflc ?

- Thdi gian cd tinh tuong ddi hay tuyet ddi ? Nd cd phu thupc vao he quy chieu quan tinh khdng ?

GV yau cdu HS lam eae bai tap trong

phia'u hpe tap dd cung cd cac kidn thflc

ve thuyet tuong ddi hep

- HS vd nha lam cae bai tap 1, 2, 3, 4

SGK.

- 6n lai djnh luat II Niu-ton dudi dang

dp bidn thian dpng lupng.

PHlfiu HOC TAP

cau 1. Tde dp cua dnh sang trong chan khdng

A. phu thupc vao phuong truydn.

B. phu thupc vao tde dp cua ngudn sang.

C. phu thupc vao phuong truydn va tde dp cua ngudn sang.

D. khdng phu thupc vao phuong truyen va vao tde dp cua ngudn sang hay may thu.

cau 2. Theo he qua cua thuyet tuong ddi hep, mpt vat chuyen dpng vdi tde do

cang ldn thi ngudi quan sat dflng ydn thdy dp dai cua vat

179

A. cang ldn.

B. cang be.

C. khdng thay ddi.

D. ban ddu tang, sau dd giam.

Cau 3. Theo he qua cua thuydt tuong dd'i hep, dp dai eua vat bj co lai theo phuong chuyen dpng, theo ti le

D. „ c

Can 4. Mpt cai thude thdng cd chidu dai 2m chuydn dpng vdi tde dp v = 0,6c

trong mpt he quy chidu quan tinh K. Do co chidu dai cua thude la

A. 0,4m. B. 0,5m.

C. 0,6m. D. 0,7m.

c a n 5. Mpt cai thude thang cd chidu dai 3 m chuyen ddng trong mpt he quy chia'u quan tinh. Mpt quan sat vian dflng yan trong hp quy chidu quan tinh tha'y cai thude cd chidu dai 2,4m. Hdi thude chuydn dpng vdi tde dp bang bao nhieu ?

A. 0,5e. B. 0,6c.

C. 0,7e. D. 0,8c.

c a u 6. Mpt vat chuydn dpng vdi tde dp 0,6c trong mpt he quy chidu quan tinh thi chidu dai ciaa vat bj co lai 0,4m. Chieu dai eua vat nhan gia trj

nao trong eae gia trj sau

A. Im. B. 2m.

C. 3m. D. 4m.

c a u 7. Mpt hien tupng vat li xay ra trong hp quy chidu quan tinh K, trong

khoang thdi gian t,. Mdt quan sat vian dflng yan trong ha quy chidu

quan tinh K2 thdy hien tupng vat li xay ra trong khoang thdi gian tj.

Bidt rang Kj chuydn dpng'thang deu vdi van tde v so vdi Kj. Ke't luan

nao sau day la dung khi ndi vd tj, t2?

A. t| >t2. B. ti <t2.

C t] - t 2 . D. t| =2t2.

180

cau 8. Hat mazdn TT" ehuydn dpng vdi van tde v = 0,99999999c va cd thdi

gian sdng At =2,2.10'*s. Theo he qua cua thuyet tuong ddi hep thi

thdi gian sdng cua hat dd la A. I,54.l0-'s. B. 15,4.10"'s. C. 154.10-'s. D. 0,154.l0-'s.

cau 9. Mpt ddng hd chuyen dpng vdi tde dp v = 0,8c. Hdi sau 1 gid (tinh theo ddng hd chuyen dpng) thi ddng hd nay chay cham hon ddng hd gdn vdi quan sat vian dflng yan bao nhiau ?

A. 20 phut. B. 30 phut.

C 40 phut. D. 50 phut.

181

BAI51

Hfi THirc ANH-XTANH GICA

K H 6 I LUONG VA NANG LLTONG

I-MUCTl£U

1. Ve kie'n thflc

- Nau dupe ha qua cua thuyet tuong ddi ve tinh tucmg ddi ciaa khdi lupng va ve mdi quan he gifla nang lupng va khdi lupng. - Viet dupe he thflc Anh-xtanh gifla khdi lupng va nang lupng va giai dupe cac bai tap van dung he thflc nay.

2. va' kl nang

- Ren luyan ki nang giai thich cac hian tupng vat li. - Ren luyen ki nang thu thap thdng tin khi doe tai lieu. - Ren luyen ki nang lam cac bai tap trdc nghiem khach quan nhieu lua chpn vd he thflc Anh - xtanh giua khdi lupng va nang lupng.

II - CHUXN BI

Giao vien

- Chudn bj phieu hpc tap eho HS.

Hpc sinh

- On lai djnh luat II Niu-ton dudi dang dp bien thian dpng lupng.

Ill - THifi'T Kfi HOAT D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chuan bi dieu kien

xua't phat



GV nau cau hdi kiem tra kidn thflc cu

- Viet bieu thflc dpng lupng cua mpt vat khdi lupng m chuydn dpng vdi van tde v ?

- Viet bidu thflc ciaa dinh luat II Niu-ton dudi dang dp bien thien dpng lupng ?

182

HS nhan thflc dupe vdn de cua bai hpc

Hoat ddng 2

Tim hieu khai niem khdi lupng tuong doi tinh



- Khdi lupng tuong ddi tinh cua vat tang khi van tde cua vat tang. Gia tri cua khdi lupng phu thupc vao ha quy chieu.

- Na'u v <£: c thi khdi lupng eua vat cd tri sd gan bang khdi lupng nghi:

m«mo.

Ddt vdn de : Theo eo hpc ed dien, dpng lupng dac trung cho chuyen dpng vd mat dpng lye hpe. Trong thuyet tuong ddi, dpng lupng tUong ddi tinh cua mpt vat chuydn dpng vdi van tde v cung dupe djnh nghia tuong ty nhu cdng thflc dinh nghia dpng lupng trong co hpc cd didn. Tuy nhian, khdi lupng trong bidu thflc dpng lupng tuong ddi tinh la khdi lupng tuong ddi tinh. Vay khdi lupng tuong ddi tinh la gi ? Xac djnh nd bang bieu thflc nhu the nao ? Bai hpc ngay hdm nay giup ehung ta tim hidu dieu dd.

GV thdng bao bidu thflc eua khdi lupng tuong ddi tinh

- Khdi lupng tuong ddi tinh cua mpt vat dupe xae dinh theo bidu thflc :

mo

trong dd mQ la khdi lupng nghi cua vat

(cdn gpi la khdi lupng tinh), la khdi lupng eua vat khi nd dflng yan.

GV yau cdu HS nhan xet ve sy phu thupc eua vat vao van tde va xae djnh khdi lupng tuong ddi tinh cua mpt ngudi ed khdi lupng nghi 60kg chuyen dpng vdi tde dp 0,8c.

183

- Ap dung cdng thflc : :

m ""0 ^

^ m - -innifo ;

Ff ' \ Hoat ddng 3

Tim hieu he thflc Anh-xtanh ; giura khdi lupng va nang lupng

HS tia'p thu, ghi nhd :

;


- Vl nang lupng va khdi lupng • luon ti le vdi nhau vdi he so' ti le •

bdng e nan khi nang lupng thay : ddi mpt lupng AE thi khdi lupng : cd thay ddi mpt lupng Am vdi ; •

AE = Am.c •

GV thdng bao ha thflc Anh-xtanh giua khdi lupng va nang lupng.

- Thuydt tuong dd'i da thiet lap ha thflc rdt quan trpng sau day gifla khdi lupng eua mpt vat (hoac mpt he vat) va nang lupng toan phdn:

J.4 V c^

He thflc nay dupe gpi la he thflc Anh-xtanh. Iheo he thflc nay, khi mot vdt eo khdi lupng m thi nd eung cd mpt nang lupng E, va ngupe lai, khi vat ed nang hrpng E thi no ed khdi lupng tuong flng lam.

GV nau cau hdi de HS hidu y nghia ciaa ha thflc

- Khi nang lucmg thay ddi mpt lupng AE thi khdi lupng ed thay ddi khdng ? Neu cd, hay tim bidu thflc toan hpc bidu didn sy thay ddi dd ?

- Hay xac djnh nang lupng ciaa vat trong trudng hpp v = 0vakhi v« ;c?

184

~Khiv = 0thi E = Eo=moC^

- K h i v - ^ c :

V 1 1 . 1 v^

=>E«moe^+-mov2


Hoat dong 4

Tim khdi lupng tuong ddi tinh va

khdi lupng nghi cua photon

HS lam viae ca nhan

Ta CO E = hi = —-A.

Gpi mp^la khdi lupng tuong ddi

2 tinh eua phdtdn , ta co: £ = nip,,c

GV the ehd hoa kidn thflc

- Khi V = 0 thi EQ = mgc , EQ gpi la

nang lupng nghi.

2 1 2 - Khi V <K c thi E « mQC + — mpv ,

gpi la nang lupng toan phdn, nang lupng toan phdn bao gdm nang lupng nghi va dpng nang cua vat.

- Theo vat li hpc cd didn, neu mpt he vat la kin thi khdi lupng va nang lupng cua nd dupe bao toan. Cdn theo thuydt tuong ddi, ddi vdi he kin, khdi lupng nghi va nang lupng nghi tuong flng khdng nhdt thiet dupe bao toan, nhung nang lupng toan phdn W dupe bao toan.

GV yau cdu HS tim khdi lupng tuong ddi tinh va khdi lupng nghi cua phdtdn anh sang

GV neu eae eau hdi gpi y - Theo thuyet lupng tfl anh sang, phdtdn flng vdi cac bfle xa don sdc ed bude sdng X va tan sd f cd nang lupng bdng bao nhiau ?

185

= ±. = — = A. 'ph

cA.

Mat khae: mop^^mp^

Ma photon ludn chuydn dpng vdi tde do khong ddi bang c, nan:

m Oph = 0.

- Nang lupng cua phdton dupe xac djnh theo ha thflc Anh-xtanh nhu the nao ?

- Khdi lupng nghi cua phdtSn dupe xac djnh theo bieu thflc nao ? Nhan xet gi vd tde dp chuyen dpng cua photdn ?

Hoat ddng 5


GV yau cdu HS lam cac bai tap trdc nghiem trong phieu hpc tap dd cung cd kia'n thflc da hpc. - HS ve nha lam cae bai tap 1,2,3 SGK.

PHIEU HOC TAP

cau 1. Ka't luan nao sau day dung khi ndi vd khdi lupng eua mdt vat ?

A. Khdi lupng cd tinh chdt tuyet dd'i.

B. Khdi lupng ed tinh ehdt tuong ddi, gia trj eua nd khong phu thuCc ha quy chieu.

C. Khdi lupng cd tinh chat tuyat- dd'i, gia trj cua nd khdng phu thuCc he quy chieu.

D. Khdi lupng cd tinh chdt tuong ddi, gia tri eua nd phu thupc he quy chidu.

cau 2. Nang lupng toan phdn cua mpt vat dflng yan ed khdi lupng 1kg la

A. 9.10'^J.

C. 9.10'°J.

B. 9.10^J.

D. 9.10'^J. Cau 3. He thflc lian ha gifla nang lupng va dpng lupng ciaa vat la

A. E^^m^c^+ipV

B. E^-m^c^+pV.

2„2 .2_2 C. E ^mgc^+p^c

2„4 .2„2 D. E^-m5cVp^c

186

can 4. Mpt hat cd dpng nang bang nang lupng nghi eua nd thi tde dp cua hat la

A. 2 ,6 .10Ws. B. 2 6 . l 0 W s .

C. 0 ,26.10Ws. D. 6 .10Ws.

cau 5. Mpt vat cd khdi lupng nghi mo chuyen dpng vdi tde dp v se cd dpng

nang bdng

A. W,=moc^ 1

- 1

1 -

B. W^^moC 1

+ \

1 -

C Wd^moC

1 -

D. W.^mQC^ + 1

\ +

Cau 6. Mpt vat cd khdi lupng nghi 1kg chuydn dpng vdi tde dp v = 0,6e. Dpng nang cua vat nhan gia tri nao trong cac gia trj sau day ?

A. ^lO'^J. 4

C. -lO^J. 2

B. - lO'^J. 4

D. lO'^J.

cau 7. Khdi lupng tuong ddi tinh cua mpt phdtdn la 8,82.10 ^^kg thi bfle xa flng vdi photon dd cd budc sdng la

A. ^ = 0,50nm.

B. ?. = 0,25^m.

C. X. = 0,05^m.

D. >. = 0,55^m.

Cau 8. Dpng lupng tuong ddi tinh cua photon la

A. p = ^c.

187

cau 9. Mpt vat CO khdi lupng nghi 1kg ehuydn dpng vdi tde dp 20m/s. Nang lupng toan phdn cua vat la

A. 9.10'^J. B. (200 + 9.10'^)J.

C. 200J. D. 209.10'^ J.

cau 10. Mpt phd tdn flng vdi bfle xa 0,5pm thi dpng lupng tuong ddi tinh ciaa

nd la

A. 1,325.10"^^kgm/s.

B. 13,25.10"^^kgm/s.

C. 132,5.10"^^kgm/s.

D. 1325.10-2^kgm/s.

188

CHWONG IX. HAT NHAN NGUYEN i f l

BA/52

CXU TAO HAT N H A N N G U Y £ N TLT - Dd HUT KHdl

I-MUCTl£U

tVe'ki^n thflc

- Neu dupe cdu tao eua hat nhdn, biet ki hiau hat nhan va don vj khdi lupng nguyan tfl.

- Suy luan ra sy tdn tai cua lye hat nhan.

- Nau dupe lye hat nhan la gi va eae dac didm cua lye hat nhdn.

- Nau dupe dp hut khdi cua hat nhan la gi va viet dupe cong thflc tinh dp hut khdi.

- Neu dupe nang lupng lian kdt hat nhan la gi va viet dupe cdng thflc tinh nang lupng lian ket hat nhan.

2. Vi ki nang

- Ren luyen ki nang dn luyen kien thflc cu.

- Ren luyen ki nang giai thich cac hian tupng vat li.

- Ren luyen kT nang suy luan logic dd tim ra lye hat nhan.

- Ren luyen kT nang lam eac bai tap trdc nghiem khach quan nhidu lya chpn phdn cdu tao hat nhan nguyan tfl, nang lucmg lian ket.

II-CHUXNBI

Giao vien

- Chudn bj phia'u hpc tap cho HS.

Hpc sinh

-r On lai kia'n thflc vd cdu lae nguyan tfl, cdu tao hat nhan, bang tudn hoan cae nguyan to da hpc trong chucfng trinh hoa hpe ldp 10 THPT.

189

Ill - THifi'T Kfi' HOAT D O N G DAY HOC


Hoat ddng 1

Kiem tra, chuan hi dieu kien i xuat phat. Dat van de

HS suy nghT ca nhan tim eau tra ldi ;

HS nhan thflc dupe van de eua bai • hoc 1

Hoat ddng 2

6n tap cac kien thflc ve cau tao ; hat nhan nguyen tfl, ddng vi va : don vi khdi lupng nguyen tfl

HS thao luan ehung toan ldp ;

- Hat nhan dupe eau tao tfl nhiftig ; hat nhd hon la prdtdn va notron. j Khdi lupng ciaa proton la j

mp= 1,67262.10"^^ kg, i

mang dien tich nguyan td +e ; khdi | lupng eua notron la i

m„-l ,67493.l0"^\g, \

khong mang dien. : - Ki hieu hat nhan nguyan tfl ciaa ;

nguyan tfl X la ^X ;

Trd giiip cua giao vien

i GV nau cau hdi kidm tra kidn thflc cu i - Hat nhan nguyan tfl dupe ca'u tao tfl i nhflng hat nhd hon la nhflng hat nao ? i Dien tich cua ehung bang bao nhiau ?

i Ddt vdn de : Khdi lupng cua hat nhan ; nguyan tfl ed bang tdng khdi lupng cua i cae nuclon cdu tao thanh nd hay khdng ? ; Tai sao cae prdtdn mang dian tich i duong lai cd the gdn kdt chat vdi nhau i trong hat nhan chfl khong ddy nhau ra i xa ? Bai hpc ngay hdm nay giup ehung i ta tim hieu didu dd.

i GV nau eau hdi dd HS dn tap cac kidn ; thflc vd hat nhan nguyan tfl da hpc trong i chuong trmh hoa hpc ldp 10 THPT.

• - Nau khdi lupng va dien tich eua cac • hat cau tao nen hat nhan nguyan tfl ?

i - Viet ki hieu hat nhan nguyan tfl cfla \ nguyan tfl X va cho bidt each xac dinh i sd hat notrdn trong hat nhan nguyan tfl ?

^ rA:lasdkhdi, A = Z+N i trong do < \

[Z: la sd hiau nguyan tfl ; Sd notron trong hat nhan nguyan |

tfl X dupe xac dinh : N = A - Z. ;

- Ddng vj la nhflng nguyan tfl ma ; hat nhan chfla cung sd prdtdn Z, ; nhung cd sd notron N khae nhau. ;

- lu la khdi lupng nguyan tfl, u ;

cd trj sd bang — khdi lupng cua •

ddng vi g C. •

=>lu« 1,66058.10"" kg. i

- Khdi lupng nguyan tfl cua thd ;

dupe tinh theo lu = 931,5Mev/c^. ;

mp= 1,67262.10"^^ kg \

«^938Mev/c^. \

m„-l,67493.lO"2'^kg \

« 9 3 9 M e v / c l j .

HS tia'p thu, ghi nhd •

Hoat ddng 3

Tim hieu nang lupng lien ket

HS thao luan ehung toan ldp ;

- Ddng vj la gi ?

- Cho biet y nghia cua I u ?

2

- Dya vao ha thflc Anh-xtanh E - me ,

hay cho biet khdi lupng cd thd do bang

don vj nao ? - Hay tinh khdi lupng eua prdtdn va

notron theo don vi MeV/c ?

GV bd sung kien thflc

- Cac hat prdtdn va notron dupe gpi

ehung la hat nucldn.

- Ne'u coi hat nhan nguyan tfl nhu mpt

qua cdu ban kinh R. Ngudi ta tha'y rang

R phu thupc sd khdi theo edng thflc :

R = l,2.10"^Â^^^

GV yau cdu HS thao luan ehung toan

ldp dd tra ldi cau hdi dat van dd cua GV.

191

- Theo djnh luat Cu-I6ng thi eac nucldn mang dien phai ddy nhau mpt lye. Tuy nhian, chflng vdn khdng rdi xa nhau vi ndu rdi xa nhau thi khdng tdn tai nguyan tfl. Vi vay, phai tdn tai mpt lye ldn hon lye Cu-ldng va cd tac dung lian ka't eac nuclon.

- Tai sao eac proton mang dien tich duong lai cd the gdn kdt chat vdi nhau trong hat nhan chfl khdng ddy nhau ra xa?

GV thdng bao

- Lye cd tac dung lian kdt cac nucldn

trong hat nhan la lye hut, gpi la lye hat

nhan. Lye hat nhan khong phai la luc

tinh dian, nd khdng phu thupc vao dian

tich cua cae nucldn. So vdi lye dien tfl

va lye hap ddn, lye hat nhan cd cudng

dp rat ldn (cdn goi la lye tuong tac

manh) va chi cd tac dung khi hai nucldn

each nhau mpt khoang each rdt ngdn,

bang hoac nhd hon kieh thude eua hat

nhan. Mudn tach cac nucldn ra khdi hat

nhan cdn phai ton nang lupng de thdng

lye hat nhan.

- Cac phep do ehinh xac da chflng to

rdng, khdi lupng m eua hat nhan

^Xbao gid cung nhd hoan mpt lupng

Am so vdi tdng khdi lupng eua cac

nucldn tao thanh hat nhan dd. Lupng

Am nay bang :

Am = [Zmp + (A - Z)mn ] - m

Am dupe gpi la dp hut khdi cua hat

nhan.

192


- Theo thuyet tuong ddi, he cdc nucldn ban ddu ed nang lupng:

E o = [ Z m p + ( A - Z ) m „ ] c '

cdn hat nhan dupe tao thanh tfl chiing thi cd nang lupng

2

E = me < EQ . Vi nang lupng toan phdn dupe bad toan, nan da cd mpt lupng nang lupng

2 •>

AE = EQ - E = Ame toa ra khi he

cac nuclon kdt hpp thanh hat nhan.

- Neu mudn tach hat nhan thanh cae,nucldn riang re, cdn phai thu nang lupng bang AE = Ame .

Nang lupng nay dung de thdng

lye tuong tac giua cae nucldn.

GV nau eau hdi de HS tim hieu nang

lupng uan ket va nang lupng lian ket

riang.

- So sanh tdng nang lupng eua cae

nucldn va nang lupng cua nguyan tfl khi

dupe tao thanh tfl cac nucldn dd.

- Khi cae nucldn lian kdt dd tao thanh hat nhan thi hp cae nuclon phai toa hay thu nang lUpng.

- Neu mudn tach hat nhan thanh cac nucldn riang re, cdn phai thu nang lupng hay toa nang lupng ? Nang lupng dd dung de lam gi ?

GV thdng bao

- Nang lupng AE = Ame gpi la nang

lupng lian ket hat nhan : W/j = Ame .

- Nang lupng lian ket tinh riang cho

mot nuclon ——i gpi la nang lupng hen

ket riang. Nd dac trung cho dp bdn vGng

ciaa hat nhan. Hat nhan cd nang lupng lian

ket riang cang ldn thi cang ben vflng.

- Ddi vdi cae hat nhan cd sd khdi A

trong khoang tfl 50 den 70, nang lupng

lian ka't riang eua ehung cd gia trj ldn

nha't, vao cd 8,8 MeV/nucldn.

TKBGVL!?12/2(NC} 193

Hoat ddng 4

Cung cd bai hoc va dinh hudng nhiem vu hpc tap tiep theo

GV yau cdu HS lam cae bai tap trong phieu hoc tap dd cung cd bai hpc. - HS vd nha lam eae bai tap 1, 2, 3, 4,5, 6 SGK. - 6n lai cac kidn thflc vd luc Lo-ren-xo va lye dien trudng da hpc d ldp 11

;THPT.

PHlfiU HOC T^P

cau 1. Kdt luan nao sau day dung khi ndi vd cdu tao eua hat nhan nguyan tfl ?

Hat nhan nguyan tfl dupe cdu tao tfl

A. cae aiectrdn.

B. cae aiectrdn va proton.

C. cac prdton va notron.

D. cac aiectrdn va ncftron.

cau 2. Cho hat nhan nguyan tfl ^Hv, kdt luan nao sau day sai ?

A. Hat nhan nguyan tfl cd 238 nucldn

B. Hat nhan nguyan tfl cd 92 aiectrdn

C. Hat nhan nguyan tfl cd 92 prdton

D. Hat nhan nguyan tfl cd 146 notron

cau 3. Kdt ludn nao sau day sai khi ndi vd cae ddng vj ?

Nhflng nguyan tfl ddng vj la nhflng nguyan tfl cd

A. cung sd prdton.

B. cung sd notron.

C. cung vi tri trong bang ha thdng tudn hoan.

D. sd notron khae nhau.

cau 4. Kdt ludn nao sau day ddng khi ndi vd don vj khdi lupng nguyan tfl ?

Trj sd eua don vi khdi lupng nguyan tfl u bang

1 12, A. —khdi lupng ddng vi eacbon gC.

194

19

B. 12 ldn khdi lupng ddng vj eacbon ^C.

C. khdi lupng ddng vi eacbon gC. 12

D. 2 ldn khdi lupng ddng vi eacbon gC. Cau 5. Ka't luan nao sau day sai khi ndi vd lye hat nhan ?

A. Lye hat nhan la lye hut.

B. Lye hat nhan la lye ed cudng dp rdt ldn.

C. Ban kinh tac dung cua lye hat nhan khoang lO'^^m.

D. Ban chdt cua lye hat nhan la lye dien tfl.

cau 6. Thd tich eua hat nhan U238 ldn hon thd tich eua hat nhan heli 2He

A. 595 ldn. B. 59,5 ldn.

C. 5,95 ldn. D. 0,595 ldn.

Cau 7. Khdi lupng ciaa hat nhan nguydn tfl 2 He la4,0015u, nang lupng lian

ka't cua hat nhan heli 2 He la

A. 2,832MeV.

B. 28,32MeV

C. 283,2MeV

D. 2832MeV.

cau 8. Nang lupng lian ke't riang cua nguyan tfl 2 He la

A. 780MeV/nucldn.

B. 708MeV/nucl6n.

C. 70,8MeV/nucldn.

D. 7,08MeV/nucl6n. .

195

BAI53

PHONG XA

I - MUC TifiU

1. Ve kie'n thflc

- Neu dupe hien tupng phdng xa la gi.

- Nau dupe thanh phdn va ban ehdt cac tia phdng xa.

- Phat bidu dupe dinh luat phdng xa va vidt dupe hp thflc ciaa dinh luat phdng xa.

- Nau dupe dp phdng xa la gi va vidt dupe cdng thflc tinh dp phdng xa.

- Nau dupe flng dung cua eac ddng vi phdng xa.

- Van dung dupe djnh luat phdng xa va khai niem do phdng xa dd giai quya't dupe

cac bai tap.

2. Ve ki nSng

- Ren luyen kT nang giai thich cac hien tupng vat li.

- Ren luyen kT nang lam eac bai tap trdc nghiem khach quan nhidu lya chpn phdn phdng xa.

- Ren luyfn kT nang thu thap thdng tin khi dpc tai lipu.

II-CHUAN BI

Gido vien

- Ve hinh 53.1 va 53.3 SGK tran gidy khd Ao-

- Chudn bi phieu hpc tap cho HS.

Hpc sinh

- On lai eae kien thflc vd lye Lo-ren-xo va lye dian trudng da hpe d ldp 11 THPT.

Ill - THif T Kt HOAT D 6 N G DAY HOC


Hoat ddng 1

Dat van de

HS nhan thflc dupc van de cua bai hoc

Hoat ddng 2

Tim hieu hien tupng phdng xa va cac tia phdng xa

HS tidp thu ghi, nhd


GV kd chuyan Ijch sfl — Nam 1986, khi nghian cihi eac ho^ ehdt phat ldn quang, nha bac hpc Bec-eo-ren da tinh cd phat hien thdy rdng, mieng urani sunfat da phat ra mpt loai bfle xa khdng nhin thay, nhung tac dung manh lan eac tdm kinh anh bpc kT trong gidy den day dat dudi mieng kinh dd. Ong gpi hian tupng nay la sy phdng xa, urani la chdt phdng xa va bfle xa phat ra la tia phdng xa. Bai hpe ngay bom nay cho phep chflng ta tim bidu kT hon ve hien tupng phdng xa.

GV thong bao khai nhipm hian tupng phdng xa - Hien tupng mpt hat nhan khdng ben vflng ty phat phan ra, phat ra cac tia phdng xa va bidn ddi thanh hat nhan khae gpi la hien tupng phdng xa. - Cac ket qua nghian cflu cho thdy, qua trinh phan ra phdiig xa chi do cac nguyen nhan ban trong gay ra va hoan toan khdng chiu tac ddng eua cac yeu td thupc mdi trudng ngoai nhu nhiet dp, ap sudt... Nhu vay, qua trinh phan ra phdng xa chinh la qua trinh ddn den sy bidn ddi hat nhan.

- Ngudi ta quy udc gpi hat nhan phdng xa la hat nhan me va hat nhan san pham phan ra la hat nhan con.

197

HS lam viec ca nhan tim eau tra ldi

- Cd ba loai tia phdng xa: phdng xa a ; phdng xa p ; phdng xa y.

- Cae tac dung : kich thich mpt sd phan flng hoa hpc, ion boa khdng khi, lam den kinh anh, xuyan thdu ldp vat cha't mdng, pha huy td bao...

- Tia a ehinh la hat nhan cua

nguyan tfl haii 2 He, dupc phdng ra

tfl hat nhan vdi tde dp khoang

2.I0V/S.

- Tia a lam idn boa manh eac nguyan tfl tran dudng di cua nd va mdt nang lupng rdt nhanh. Vi vay, tia a ehi di dupc tdi da khoang 8 cm trong khong khi va khdng xuyen qua dupe td bia day 1mm.

- Cd hai loai tia p :

p" la cac aiectron (ki hiau _ie).

p" la cae pdzitron, hay aiectron

duong (kihieu +ê).

~ Tia p la cac hat phdng ra vdi tde

dp ldn, gdn bang tde dp anh sang.

Tia p cung lam ion boa mdi

trudng nhung yeu hon tia a. Vi

vay tia p cd the di dupc quang

dudng dai hon, tdi vai met trong khong khi va ed thd xuyen qua dupe la nhdm day c5 milimet.

- Hat so cap mdi trong phan ra p la notrino (ki hieu v) va phan ncrtrind (ki hiau v) . Cac hat nay

GV yau cdu HS doe mue 2 SGK dd tim hidu cdc tia phdng xa va tra ldi cac cau hdi - Cd mdy loai tia phdng xa ? Ke tan cac loai tia phdng xa va nau nhflng tac dung eua ehung ?

- Ban chdt tia phdng xa a la gi ? Nau cae tinh chdt cua nd ?

- Co mdy loai tia p ? Ban chat cua cac

tia p ? Nau eac tinh ehdt eua tia p ?

- Nha vat li Pao-U da tien doan sy tdn tai cua mpt hat so cap nao ? Dac didm ciaa hat so cdp dd ?

198

khdng mang dian, cd khdi lupng nghi bang 0, chuyen dpng vdi tde dp xdp xi bang tde dp anh sang. - Tia y la sdng dian tfl cd budc

sdng rdt ngdn (dudi 10"^^ m), cung la hat phdtdn cd nang lupng cao. - Tia y cd kha nang xuyan tha'u

ldn hon nhidu so vdi tia a va p.


•

- Ban chdt cua tia y la gi ? Neu cac tinh cha't cua nd ?

GV tie'p tuc nau eau hdi, yau cdu HS quan sat hinh ve va tra ldi

- Cho cae tia phdng xa a, y, p"di qua

vung cd tfl trudng ddu nhu hinh ve, hay didn tan cua cae tia phdng xa vao hinh ve cho dung va giai thich tai sao ?

- Hinh ve dudi day md ta kha nang xuyan tha'u cua cae tia phdng xa qua vdt chdt, hay didn tan cac tia phdng xa vao hinh ve eho dung ?

Tdm bia day 1mm

m La nhfim d&y vai mm

Ta'm betfing day

199

Hoat ddng 3

Nghien cflu dinh luat phdng xa, dp phdng xa


- Sau khoang thdi gian T thi mdt nfla sd hat nhan hien ed bj phan ra, bie'n ddi thanh hat nhan khae.

No 2

No 4

N,

HayN(kT)=No.2 - k


In 2

N(t) = No.2 T^Noe T

GV yau cdu HS quan sat dd thi hinh 53.3 SGK va traldi eau hdi - Gia sfl d mpt thdi didm xac dinh nao dd, chpn thdi diem ban ddu t = 0, khdi lupng chat phdng xa la mo va sd hat nhan la No. Dd thi hinh 53.3 SGK bieu didn sy thay ddi sd hat nhan chat phdng xa theo thdi gian t. Hay vidt bieu thflc toan hpe bidu didn sy phu thupc dd ?

GV nau eae cau hdi gpi y - Sau mdi khoang thdi gian T thi sd hat nhan cha't phdng xa thay ddi nhu the nao? - Sd hat nhan eua chdt phdng xa chua bj phan ra d cac thdi didm T, 2T, 3T,..., kT ?

- Vi qua trinh phan ra la lidn tuc nan c6

the thay k = —, cd the bieu didn sy phu

thupc cua sd hat ehdt phdng xa theo thdi gian nhu thd nao ?

GV thong bao

- T gpi la ehu ki ban ra cua chdt phdng xa.

In 2 0,693 - Dat X = gpi la hang sd

T T phdng xa, dac trung cho timg loai chdt

phdng xa. Khi dd ta ed : N(t) = NQC"^'.

- Vi khdi lupng ti la vdi sd hat nan khdi lupng m eua eha't phdng xa cung giam theo thdi gian, vdi cung quay luat nhu sd hat nhan N :

200


At " =>H = XN

-Xt -DatHo = A.No=>H = Hoe"' \


m(t) = moe ^

Bieu thflc N(t) - NQC"^' ; m(t) = mQc" '

bieu thi djnh luat phdng xa: Trong qua trinh phan ra, sd bat nhan chdt phdng xa giam theo thdi gian theo dinh luat ham sd mu.

GV nau cau hdi de HS tim bidu thflc ciaa dp phdng xa - Dd dac trung cho tinh phdng xa manh hay yeu cua mpt lupng chat phdng xa, ngudi ta dung dai lupng gpi la d6 phdng xa, dupc xac djnh bang sd hat nhan phan ra trong mpt giay. D6 phdng xa dac tnmg cho tde dp phan ra. Hay vidt bidu thflc cua dp phdng xa ?

GV thdng bao - D6 phdng xa cua mpt lupng ehdt phdng xa tai thdi diem t bang tich cua hdng sd phdng xa va sd lupng hat nhan phdng xa chfla trong lupng chat dd d thdi diem t.

~ Dp phdng xa eua mpt lupng chdt phdng xa giam thep thdi gian theo eung quy luat ham sd mu gidng nhu sd hat nhan cua nd.

- Don vi cua dp phdng xa la becoren, ki hieu Bq, bang 1 phan ra/giay. Trong thyc te ngudi ta cdn dung don vi la curi, ki hieu la Ci:

lCi = 3,7.l0^^Bq

ImCi = 10"^Ci

lpCi = 10"^Ci

201

Hoat ddng 4

Tim hieu ddng vi phdng xa va cac flng dung

HS lam viae ca nhan tim cau tra ldi

- Cd hai loai ddng vj phdng xa la ddng vj phdng xa ty nhian va ddng vj phdng xa nhan tao.

Ddng vi phdng xa ty nhian la ddng vj phdng xa cd sdn trong ty nhian.

Ddng vj phdng xa nhan tao la dpng vi phdng xa do con ngudi che tao ra.

- Cac flng dung cua ddng vj phdng xa ty nhian hoac nhan tao :

Trong y hpe, ngudi ta dua eae ddng vi phdng xa khdc nhau vao CO thd dd theo doi sy tham nhap va di chuydn ciia eac nguyan td nhaft dinh trong co thd ngudi. Chung dupc gpi la nguyan tfl danh ddu; ta se nhan dian dupc ehung nhd cae thia't bi ghi bfle xa. Nhd phucfng phap nguyan tfl danh ddu, ngudi ta cd thd biet dupe ehinh xae nhu cdu vdi cac pguyan td khae nhau cua CO thd trong tfl thdi ki phat tridn cua nd va tinh trang banh li cua eae bp phan khae nhau eua co thd, khi thfla hoac thieu nhung nguyan td nao dd.

Cac nha khao ed hpc da sfl dung phuong phap xae dinh tudi theo lupng eacbon 14 dd xac djnh nian dai cua eac cd vat gde sinh vat khai quat dupc.

GV yau cdu HS dpc mue 4 SGK, sau do tra ldi cac eau hdi dd- tim hidu ddng vi phdng xa va eac flng dung - Cd mdy loai ddng vj phdng xa ? Nau eac flng dung eua nd ?

202

Hoat ddng 5

Cung cd bai hoc va dinh hudng nhiem vu hoc tap tie'p theo

GV yau cau HS lam cac bai tap trong phia'u hpe tap dd cung ed bai hpe.

- HS ve nha lam eae bai tap 1, 2, 3, 4, 5 SGK.

- On lai khai niem phan flng boa hpc va eac dinh luat bao toan da hpc trong Co hpe.

PHlfiu HOC T^P

Cau 1. Cho eae tia phdng xa a, p, ydi qua tfl trudng thi

A. tia a khdng bj leeh trong tfl trudng.

B. tia p khdng bj lach trong tfl trudng.

C. tia y khdng bj lach trong tfl trudng.

D. tia a, p, y khong bi lech trong tfl trudng.

cau 2. Ban chdt tia phdng xaala

A. hat nhan nguyen tfl jH.

B. hat nhan nguyan tfl 2 He.

C. hat nhan nguyan tfl 'gO.

D. hat nhan nguyan tu 92U.

Cau 3. Ket luan nao sau day sai khi ndi vd tia phdng xay?

A. Ban chdty la sdng dien tfl ed bude sdng ngan.

B. Tia Y ed kha nang xuyan thdu ldn.

C. Tia y la hat phdtdn cd nang lupng cao.

D. Tia Y bi lech trong dian trudng giua hai ban lu dien.

cau 4. Ke't luan nao sau day dung khi ndi vd hian tupng phdng xa ?

A. Khi tang nhiet dp, hian tupng phdng xa xay ra manh hon.

B. Khi tang ap sudt khdng khi xung quanh mpt chdt phdng xa, hien tupng phdng xa xay ra manh hon.

203

C. Phdng xa la hien tupng mpt hat nhan ty dpng phdng ra cae tia phdng xa.

D. Mudn didu ehinh qua trinh phdng xa ta phai dung dian trudng manh hoac tfl trudng manh.

cau 5. Chu ki ban ra la khoang thdi gian

A. dd cho mpt nua sd hat nhan nguyan tfl cha't phdng xa bidn thanh cha't khae.

B. de eho sd hat nhan nguyan tfl ehdt phdng xa phan ra hdt,

C. de cho 0,25 khdi lupng chdt phdng xa bj phan ra.

D. dd eho mpt nfla sd hat nhan nguyan tfl eha't phdng xa khdng cdn kha nang phan ra.

1 * ! 1

cau 6. lot phdng xa 531 dung trong y te cd ehu ki ban ra T = 8 ngay. Liic

dau cd mo = lOOg chat nay. Sau t = 24 ngay khdi lupng idt cdn lai la

A. 50g. B. 40g. C. 30g. D. I2,5g.

cau 7. lot phdng xa 531 dung trong y te cd chu ki ban ra T = 8 ngay. Luc

ddu cd mo = 200g chat nay. Sau bao nhiau ngay thi lupng idt cdn lai la lOOg ?

A. 4 ngay. B. 8 ngay.

C. 16 ngay. D. 20 ngay.

204

BAI54

P H A N LfNG HAT N H A N

I-MUCTlfiU

1. Vi kien thufc

- Nau dupc phan ihig hat nhan la gi ?

- Phat bidu dupc dinh luat bao toan sd khdi, bao toan dien tich va bao toan nang lupng toan phdn va dinh luat bao toan dpng lupng trong phan flng hat nhan.

- Via't dupc phuong trinh phan flng hat nhan va tinh dupc nang lupng toa ra hay thu vao trong phan flng hat nhan.

2. Vi kl nang

- Ren luyan kT nang giai iHich cac hien tupng vat li.

- Ren luyen kT nang lam cae bai tap trdc nghiem khach quan nhidu lya chpn phdn phan flng hat nhan.

- Ren luyen kT nang thu thap thdng tin khi doe tai lieu.

II-CHUXNBI

Gido vien

- Phia'u hpc tap cho HS.

Hpc sinh

- On lai khai niem phan flng hoa hpc va cac dinh luat bao toan da hpc trong Co hpc.

ffl - THlfiT Kfi' HOAT D 6 N G DAY HOC


Hoat dong 1

Kiem tra, chuan bi dieu kien xuat phat. Dat va'n de

HS suy nghi ca nhan tim cau tra ldi


GV nau eau hdi kiem tra kie'n thflc cu

- Phdng xa la gi ? Nau eae tia phdng xa

va ban chat eua ehung ?

205

HS nhan thflc dupe vdn dd cua bai hpe

Hoat ddng 2

Tim hieu ve phan flng hat nhan



- Sy ty phan ra eua mpt hat nhan thanh cae hat nhan khae dupc gpi la phan flng hat nhan vi dd la qua trinh ddn den sy bie'n ddi hat nhan.

- Hai hat nhan tuong tac vdi nhau tao thanh cae hat nhan khae dupc gpi la phan flng hat nhan. Phuong trinh phan flng dupc md ta :

Ddt vdn de : Vdi viec kham pha ra hien tupng phdng xa, udc mo eua cac nha gia kim thuat thdi Trung cd da trd thanh hian thyc : mpt nguyan td nay da bidn ddi thanh mpt nguyan td khae. The nhung, lieu cd each nao tao ra va didu khidn dupc qua trinh bien ddi hat nhan nhu vay hay khdng ? Bai hpe ngay hdm nay giup ehung ta tim hidu didu dd.

GV gidi thieu vd thi nghiem cua Ro-do-pho va thdng bao khai niam phan flng bat nhan

- Nam 1909, nha bac hpe Ro-do-pho da cd mpt phat minh ndi tidng, dd la tao ra dupc sy bidn ddi hat nhan. Ong cho chum hat a, phdng ra tfl ngudn phdng

xa pdldni Po, ban pha nito ed trong khdng khi. Kdt qua la, nito bj phan ra va bien ddi thanh dxi va hidrd. Qud trinh ddn de'n sy bidn ddi hat nhan nhu vay, gpi la phan flng hat nhan. - Phan iitig hat nhan la mpi qua trinh ddn ddn sy bidn ddi hat nhan.

GV nau eau hdi dd HS tim hieu vd cdc phan flng hat nhan

- Sy ty phan ra cu^ mpt hat nhan chdt phdng xa da hpe d bai 53 cd dupe gpi la phan ihig hat nhan khdng ?

- Cho hai hat nhan tuong tac vdi nhau tao thanh eac hat nhan khae cd dupc gpi la phan irng hat nhan khong ? Viet phuong trinh md ta sy bien ddi dd ?

206

A + B ^ C + D

- Trong trudng hpp phdng xa :

A - > B - H C

A la hat nhan cha't phdng xa, B la

hat nhan san phdm, C la tia phdng

xa a hoac p.


Hoat ddng 3

Tim hieu cac dinh luat bao toan

trong phan flng hat nhan

HS lam viae ca nhan tim cau tra ldi

- Djnh ludt bao toan sd nucldn : Trong phan flng hat nhan, tdng sd nucldn eua cac hat tuong tac bang tdng sd nucldn eua eae hat san'phdm.

- Dinh luat bao toan dien tich : Tdng dai sd cae dian tich eua eae hat tuong tac bing tdng dai sd cac dien tich eua eac hat san phdm.

- Trong trudng hpp phdng xa, phucmg trinh cua phan flng hat nhan dupc viet nhu tha' nao ? Nau y nghia eua cac dai lupng trong phuong trinh ?

GV thdng bao

- Nam 1934, hai dng ba Gid-li-d Quy-ri dung hat a bdn pha mpt la nhdm, ldn ddu tian da tao ra dupc ddng vj phdng

xa nhan tao phdtpho \^P cd tinh phdng

xa p" Tfl dd da'n nay, ngudi ta da tao ra

dupc hang nghin ddng vj phdng xa nhan

tao nhd cae phan flng hat nhan.

GV yau cdu HS dpc mue 2 SGK va phat

bidu eae djnh luat bao toan trong phan

ling hat nhan, sau dd viet dinh luat bao

toan sd nuclon va djnh luat bao toan

dien tich cho phan ung hat nham

^ ' A + ^ ^ ' B ^ ^ ^ C - h ^ - ' D /•l Z^ Z,3 Z,4

207

- Djnh luat bao toan nang lupng toan phdn: Tdng nang lupng toan phdn eua cac hat tuong tac bang tdng nang lupng toan phdn eua cac hat san phdm.

- Djnh luat bao toan dpng lupng: Vecto tdng dpng lupng cua cac hat tuong tac bang vecto tdng dpng lupng eua eae hat san pham.

- Djnh luat bao toan sd nuclon va dinh luat bao toan dian tich eho phan ihig hat nhan :

^ • A + ^ ^ B ^ ^-X-F^^D

| A I + A 2 = A 3 + A 4

| Z i + Z 2 = Z 3 + Z 4

- Do nang lupng toan phdn (gdm ca dpng nang va nang lupng nghi) dupc bao toan nen khdi lupng nghi khPng bao toan. Din de'n, khdi lupng khdng dupc bao toan trong phan flng hat nhan.

Hoat ddng 4

Tim hieu ve nang lupng trong phan flng hat nhan


- Neu m > m o , tfle la tdng nang

lupng nghi ciia cae hat tao thanh ldn hon tdng nang lupng nghi cua cac hat nhan tham gia phan utig. Mudn phan img xay ra thi nang lupng toan phan phai dupc bao loan, tfle la edn phai eung cap nang lupng cho cac hat tham gia phan flng dudi dang dpng nang.

— . . •

- Trong phan flng hat nhan, khdi lupng

cd dupe bao toan khdng ? Tai sao ?

GV nau cau hdi dd HS tim hidu vd nang

lupng trong phan flng hat nhan

- Xet phan flng hat nhan A + B ^ C + D,

gpi mo = m^ + mg la tdng khdi lupng

nghi cua cac hat A, B ; m = m ^ + mp la

tdng khdi lupng nghi cua cae hat C, D.

Didu kien dd xay ra phan flng la gi ndu

m > m o ?

208

- Theo djnh luat bao toan nang lupng toan phdn, nang lupng edri cung cdp cho phan ihig bang:

W = (m-mo)e^ + Wd ^

- Na'u m < mo va eae hat nhan A,

B dflng yan thi phan flng hat nhan toa nang lupng, lupng nang lupng

toarala : W = (mo -m)c^

- Nang lupng toa ra dudi dang dpng nang cua hat C va D hoac nang lupng cua phdtdn y.

- Do m < mo nan cae hat nhan tao

thanh ed do hut khdi ldn hon cac hat nhan ba ddu, nghTa la cae hat sinh ra bdn vung hon eac hat ban ddu.


- Gia sfl eac hat tao thanh cd tdng dpng nang la Wj thi cdn phai eung cdp eho

phan flng mpt lupng nang lupng bang bao nhiau dd phan flng xay ra ?

- Neu m < mo va eac hat nhan A, B

dflng yan thi phan ihig hat nhan la toa nang lupng hay thu nang lupng ? Tinh lupng nang lupng dd ?

- Nang lupng toa ra dudi dang nao ? Nhan xet gi vd tinh ben vflng cua hat nhan tao thanh sau phan flng so vdi cae hat nhan ban ddu ?

GV thdng bao vd hai loai phan flng hat nhan toa nang lupng - Phan flng hat nhan toa nang lupng xay ra khi eac hat sinh ra bdn vflng hon so vdi cae hat tuong tac ban ddu. Theo ket qua tinh toan nang lupng lian ket riang cfla eac hat nhan cd sd nucldn A khae nhau da cho thdy cd thd xay ra hai loai phan irng hat nhan toa nang lupng:

Hai hat nhan rdt nhe (cd sd khdi A < 10), nhu hidrd, heli... hpp lai thanh hat nhan nang hon. Vi su tdng hpp hat nhan chi cd thd xay ra d nhiat dp cao nen phan irng nay gpi la phan ihig nhiat bach.

VD : phan flng ^H + ^H = ^He+^n,

toa nang lupng khoang ISMeV Cac hat

7KBGVLyi2/2(NC) 209

' : : ' " • • f

Hoat ddng 5


nhan ^H va ^H cd nang lupng lien kdt

rieng tuong flng bang 1,11 va 2,83

MeV/nuclon ; edn hat nhan 2^6 cd

nang lupng lien ket riang ldn hon, bang 7,04 MeV/ nucldn.

Mpt hat nhan nang vd thanh hai manh nhe hon (cd khdi lupng cung cd). Phan flng nay gpi la phan flng phan hach. Chang hat hat nhdn urani, plutdni... hdp thu notron va vd thanh hai hat nhan cd sd khdi A vao loai trung binh. VD: phan ihig

toa nang lupng khoang l85MeV. Hat

nhan 92 U ed nang lupng lian kdt riang

bang 7,59 MeV/nucldn, edn cac hat

nhan 38 Sr, ^j^Xe cd nang lupng lian

ka't riang ldn hon, tucfng flng bang 8,59 va 8,29 MeV/ nucldn.

GV yau cdu HS lam eac bai tap trong phia'u hpe tap dd eung cd bai hpc.

- HS vd nha lam cac bai tap 1, 2, 3, 4, 5 SGK.

- On lai khai niem phan flng hoa hpc va cac djnh luat bao toan da hpc trong Co hpc.

210

FHIjgu HOC TAP

Can 1. Kdt luan nao trong cac kdt luan sau day dung khi ndi vd phan flng hat nhan ?

A. Phan ihig hat nhan la su va cham gifla eac hat nhan.

B. Phan ung hat nhan la moi qua trinh ddn den sy bien ddi hat nhan. C. Phan irng hat nhan la sy tac dpng ban ngoai lam hat nhan tach thanh

cae hat nhan khae.

D. Phan ihig hat nhan cd ban chdt gidng nhu phan flng boa hpc. cau 2. Cae phan flng hat nhan khong tuan theo cae djnh luat nao sau day ?

A. Bao toan nang lupng toan phdn. B. Bao toan dien tich.

C. Bao toan khdi lupng. D. Bao toan dpng lupng tuong ddi tinh.

cau 3. Ka't luan nao sau day diing khi ndi ve phan flng hat nhan toa nang lupng ?

A. Cac hat nhan sinh ra cd nang lupng lian kdt ldn hon cae hat nhan tham gia phan flng.

B. Cac hat nhan sinh ra cd nang lupng lian kdt be hon cac hat nhan tham gia phan flng.

C. Cac hat nhan sinh ra cd nang lupng lian ket bang cac hat nhan tham gia phan flng.

D. Cae hat nhan sinh ra ludn ed nang lupng lian ket nhd hon IMeV.

Cau 4. Cho mpt phan irng hat nhan la phdng xa a : ^ ^ ^ 2ê+ ^-Y. Ket luan

nao sau day dung khi ndi vd sd khdi va nguyan tfl sd eua hat nhan san phdm?

("A' = A + 4 B.

[Z' = Z + 2

rA' = A + 2 D.

[Z' = Z + 4

Cau 5. Cho mpt phan flng hat nhan la phdng xa p": ^X -> _°e + Y. Kdt luan nao

sau day sai ?

A. Hat nhan Y dflng sau hat nhan X mpt d trong bang ha thdng tudn hoan.

211

B. Hat nhan Y ed sd khdi va nguyan tu sd ; 2+1Y.

C. Trong phan flng ed sy bien ddi ciaa mpt hat notrdn : n -> p + _ê + v.

D. Trong phan flng cd sy bien ddi cua mpt hat prdton : p -> n + _ e + v.

cau 6. Cho mpt phan flng hat nhan la phdng xa p"": ^X -> + e +Y. Kdt luan nao

sau day dung ?

A. Hat nhan Y dung sau hat nhan X mpt 6 trong bang he thdng tudn hoan

B. Hat nhan Y cd sd khdi va nguyan tfl sd : z+^Y.

C. Trong phan irng ed sy bien ddi eua mpt hat prdtdn : p—>n + ^]e + v.

D. Hat nhan Y va X la hai hat nhan ddng vi.

cau 7. Cho phan flng hat nhan : g Bi ~> Y + JJPo. Kdt luan nao sau day dung ?

A. Phan flng hat nhan la phan ra phdng xa a.

B. Phan flng hat nhan la phan ra phdng xa p"

C. Phan flng hat nhan la phan ra phdng xa p"

D. Phan flng hat nhan la phdn ra phdng xa y.

can 8. Hat nhan X trong phan flng hat nhan '9F + p-> 'gO + X la

A. ^Li. B. ^Be.

C. | H . D. ^He.

212

BAI55

BAI TAP vt PHONG XA vA PHAN LJNG HAT N H A N

I -MUCTl£u

1. Va' kia'n thflc

- Van dung dupe djnh luat phdng xa dd giai quyet eac bai toan don gian vd phdng xa.

- van dung dupe eac kia'n thflc vd phan flng hat nhan va cac dinh luat bao toan trong phan flng hat nhan dd giai quydt mdt sd bai toan vd phan flng hat nhan.

2. va' ki nang

- Ren luyan kT nang giai toan vat li phdn phdng xa va phan ihig hat nhan.

II-CHUXNBI

Gido vien

- C3iudn bi phieu hpc tap cho HS.

Hpc sinh

- On lai Bai 53 va Bai 54:

III - THifiT Kfi HOAT D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chuan hi dieu kien

xuat phat

HS suy nghT ca nhan tim cau tra ldi



- Phat bieu cac djnh luat bao toan trong

phan flng hat nhan ?

- Via't bidu thflc cua djnh luat phdng xa

va bieu thflc tinh dp phdng xa ?

213

Hoat ddng 2

Lam bai tap 1 dd biet each van dung cac dinh luat luat bao toan trong phan flng hat nhan va dinh luat phdng xa


a) Ki bieu hat nhan con X la ^X,

phuong trinh phan dug ed dang

Ap dung djnh luat bao toan sd khdi va djnh luat bao toan dien tich : 210 = 4 + A ; 8 4 = 2 + Z Ta tim dupe : A = 206 va Z = 82. Vay hat nhan X la hat nhan ddng

vi ehi 82 Pb' cd cdu tao gdm 82 prdtdn va N = 206 - 82 = 124 notron.

b) Dp phdng xa cua mdu pdldni sau 3 chu ki ban ra la : H = XN

0,693 trong dd : ^ -

T

Sd hat nhan pdldni ban ddu la :

mo N o - N ^

A

Vdi mo=0,01g ; A = 210g. Sau

thdi gian t = 3T sd hat nhan pdldni cdn lai (chua bi phan ra phdng xa) la ;

^ j_J io _ N o _ N Q _ N A m o

2 l T

8A

GV yau cdu HS lam bai tap 1 trong phidu hpe tap theo nhdm, sau dd dai dian nhdm lan bao cao kdt qua.


- Phuong trinh phan utig viat cho tmdng hpp chat phdng xa ed dang nhu thd nao ?

- Ban ehdt cua hat a la gi ?

- Ap dung dinh luat nao de tim sd khdi va sd hieu nguyan tfl cua hat nhan san phdm?

~ Viet cdng thflc tinh dp phdng xa ? Mudn tinh dupe dp phdng xa ta cdn phai xac djnh dupc nhung dai lupng nao ?

- He sd phdng xa dupe xac dinh nhu thd nao ?

- Dd xac dinh N ta edn ap dung c6ng thflc nao va phai xae dinh tham dai lupng nao ?

214

Vdi T = 138 ngay =138.24.3600 s, ta ed :

H = A.N

^0,693j^jÔ,693.NAmo

T 8AT

H 01 2,084.10"Bq.

c) Sd hat nhan poldni cdn lai sau t = 4T la : T . . _ N o ^ N o ^ N o

1 2 * 16 2T

Khdi lupng pdtdni cdn lai sau thdi gian t = 4T la :

m = N, • N ' =

AN(

16N,

Sd hat nhan pdldni da bj phan ra phdng xa sau thdi gian t dd :

15No AN = N o - N ' =

16 Sd hat nhan AN nay cung chinh bdng sd hat nhan X dupc tao ra trong thdi gian t = 4T. Vay khdi lupng chat X dupe tao ra Id:

A' . . . 15NoA' my = AN = —

"" NA 16NA

vdi A' = 206. Tfl dd ta rim dyoe ti sd ; m- _ A ^ 210

m. " 1 5 A ' ~ 15.206 -0 ,086

- Mudn tinh khdi lupng cua poldni sau 4 ehu ki ban ra ta phai tinh dupe dai lupng nao ? - Mudn tinh dupe khdi lupng cua hat nhan X ta cdn phai tinh dupc sd hat nhan X dupe tao thanh. Xac dinh nhu the nao ? - Sd hat nhan poldni bj phan ra cd mdi quan ha nhu the nao dd'i vdi sd hat nhan X duoe tao thanh ?

Hoat ddng 3

Lam bai tap 2 de bidt each lam bai toan xac djnh tudi cua mau vat

HS lam bai tap theo nhdm, sau dd dai dian nhdm lan bao cao kdt qua

GV yau cdu HS lam bai tap 2 trong phidu hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua.

215

a) Phuong trinh cua phan flng phan ra la :

' ^ C ^ P " + X + gv

hay ^ ^ C ^ > " + ^ X + gv

Ap dung djnh luat bao toan sd khdi va bao toan dien tich , ta cd: 14 = 0 + A ; 6 = - l + Z

=>Z = 7; A= 14

Nhu vay, hat nhan X chinh la hat

nhan nito '7N.

vay ta cd phuong trinh :

b) Ta cd :

mo m =

2T

m

mo

Theo dd ra : m mo

2T

-i ~8

Tfldd:

_L = i l ^ l = 3=>t = 3T 1 8 2 T

2T

I = 3.5600 =16800 nam.

Vay, sau t = 16800 nam lupng

chat phdng xa chi cdn bdng -8

lupng chat phdng xa ban ddu.

e) Ki hieu t la khoang thdi gian ma mdu gd cd dai da ehdt, ta ed :

H=Hoe -; . t

GV nau eac cau hdi gpi y - Phuong trinh phan flng viet cho trudng hpp chdt phdng xa cd dang nhu the nao ?

- Ban cha't cua hat p~ la gi ?

- Trong phan ra p"- xudt hian them hat

nao?

- Ap dung djnh ludt nao dd tim sd khdi va sd hieu nguyan tfl cua hat nhan san phdm?

- Lupng chdt phdng xa sau khoang thdi gian t dupe xae djnh bang bieu thflc nao ?

- Theo dd bai, ta rut ra dupc bidu thflc nhu the nao ?

- Dp phdng xa cua mdu gd cd dai dupc xac djnh bang cdng thflc nao ? Trong cdng thflc dd, dai lupng nao da biet ?

216

vdi Ho= 0,250Bq ; H = 0,215Bq.

Tfldd:

^t = l n ^ = . l n

t =

0,250 H 0,215

0,1508 0,1508T X 0,693

= 0,1508

«1250 nam.

Hoat ddng 4

Lam bai tap 3 de van dung djnh luat bao toan nang lupng trong phan flng hat nhan HS lam bai tap theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua

a) Phuong trinh phan flng;

^He+^^N^lH + ^X

Ap dung cac djnh luat bao toan sd khdi va bao toan dian tich tim dupc:

A= 17;Z = 8

Do dd la hat nhan 'gO

Tathdy : mo= mj^+ mj.j= 18,0007u

m = mp+mx - 18,0020u.

Nhu vay, mo< m phan flng thu

nanglupng, vdi:

AE = (mo -m)c^ = -1,2103 MeV

b) Theo djnh luat bao toan nang lupng ta ed :

moc' + W^ = mc2 + Wo + Wp (1)

GV yau cdu HS lam bai tap 3 trong phieu hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao kdt qua.

- Phuong trinh phan img hat nhan ed dang nhu tha'nao?

- Ap dung djnh luat nao de tim sd khdi va sd hieu nguyan tfl eua hat nhan san phdm?

- Mudn bia't phan flng la thu nang lupng hay toa nang lucmg ta phai tinh dupc dai lupng nao?

- Nang lupng cua eae hat trudc phan flng va sau phan flng ?

- Ap dung djnh luat bao toan nang lupng toan phdn ta dupc didu gi ?

217

Trong dd W„,Wo,Wp la ddng

nang cua hat a , bat nhan 'Ôva

hat potdn. Vi hai hat sinh ra,

0 va prdtdn cd ciing tde dp, nen ta cd:

^ = - W o = i n o w ^ (2) Wp mp mp

tfl (1), (2) thay sd ta dupe:

Wp=0,156MeV

suy ra tde dp cua pdtdn :

V p = j e-«5,5 .10V/s . ^ n i p

- Dpng nang cua oxi va prdtdn ed quan ha vdi nhau nhu thd nao ?

PHlfiu HOC T^P

cau 1. Pdldni g4Po la nguyan td phdng xa a, nd phdng ra mpt hat a va bian

ddi thanh hat nhan con X. Chu ki ban ra eua pdldni la T = 138 ngay.

a) Viet phuong trinh phan img. Xac djnh cdu tao, tan gpi eua hat nhan X.

b) Mpt mdu pdldni nguyan chat cd khdi lupng ban ddu 0,Olg. Tinh dfi phdng xa eua mdu chat tran sau 3 chu ki ban ra. Cho bie't sd A-vd-ga-drd

N A = 6,022.10"^^ nguyen tfl/mol.

e) Tinh ti sd gifla khdi lupng pdldni va khdi lupng cha't X trong mdu chdt tran sau 4 chu ki ban ra.

cau 2. Hat nhan g^ 1 rnpt ehdt phdng xa, nd phdng ra tia p" cd chu ki ban ra la

5730 nam.

a) Viet phuong trinh phan flng phan ra.

b) Sau bao lau lupng chat phdng xa eua mpt mdu ehi cdn bang - lupng 8

eha't phdng xa ban ddu cua mdu dd ?

218

c) Trong cay edi cd chdt phdng xa '^C. Dp phdng xa cua mpt mdu gd tuoi

va mpt mdu gd cd dai da chet cung khdi lupng ldn lupt la 0,250Bq va

0,215Bq. Xac djnh xem mdu gd ed dai da chet each day bao lau ?

Cau 3. Ban hat a cd dpng nang 4MeV vao hat nhan '7N dimg yen thi thu dupc

mpt hat prdton va mpt hat nhan X.

a) Tim hat nhan X va tinh xem phan flng dd toa ra hay thu vao nang lupng bao nhiau MeV.

b) Gia sfl hai hat sinh ra cd eung tde dp, tinh dpng nang va tde dp cua pdtdn.

Cho:

m^= 4,0015u ; mx =16,9947u;

m^ = 13,9992u; mp = 1,0073 u;

lu=931 MeV/c^ e = 3 . 1 0 V / s .

219

BAI56

P H A N ITNG P H A N H A C H

I -MUCTl£U ; •

l .Ve kie'n thflc '

- Nau dupe phan flng phdn bach la gi va viet dupc mpt vi du vd phuong trinh phan flng nay. - Nau dupc phan flng day chuydn la gi va eac dieu kian dd phan flng nay xay ra.

- Nau dupe cae bp phan chinh cua nha may dien hat nhan.

2. Va'kinang ._

- Ren luyen kT nang tim hidu utig dung kT thuat vat li. - Ren luyan kT nang lam cae bai tap trdc nghiem khach quan nhidu lya chpn phdn phan img phan hach. - Ren luyan kT nang thu thap thdng tin khi doe tai lieu.

II-CHUXNBI

Gido vien

- Ve hinh 56.1, 56.2, 56.3, 56.4 trdn gia'y khd Ao-

- Phia'u hpe tap cho HS.

Hpc sinh

- On lai cac kie'n thflc vt phan flng hat nhan.

Ill - THifi'T K£' H O A T D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chuan bi dieu kien xua't phat

HS suy nghT ca nhan rim eau tra ldi


GV nau cau hdi kidm tra kieh thflc cu - Nau hai loai phan flng hat nhan toa nang lupng. La'y vi du.

220

HS nhan thflc dupc vdn dd cua bai hoc

Ddt vdn de : Bai hpc ngay hdm nay chflng ta di nghian cflu ve phan ihig phan bach va nhirng flng dung cua nd trong kT thuat.

Hoat ddng 2

Tim hieu vd su phan bach


HS lam viec ca nhan 235 U ha'p thu mpt notron cham

chuyen thanh ^^Û, "Û dtrang

GV kd chuyen Ijch sfl ve thi nghiem phan hach urani

- Nam 1939, hai nha hoa hpe ngudi Dfle la Han va Xto-ra-xman da lam thi nghiem diang notron ban vao urani. Ket qua cho tha'y hat nhan urani vd thanh hai hat nhan cd khdi lupng nhd hon. Kem theo qua trinh phan hach nay cd mdt so notron dupe giai phdng, bay ra.

- Nhieu thi nghiam tiep theo da cho tha'y rdng phan flng phan hach cd thd xay ra nhidu each vd khae nhau. Vi du : DiJng notron nhiat (cdn gpi la notron cham) ed nang lupng c5 0,01eV bdn vao

U, ta cd phan flng :

trong dd, X, va X2 la cae hat nhan cd sd khdi trung binh (tfl 80 ddn 160) va hdu het la cac hat nhan phdng xa ; k la sd ncftron trung binh dupe sinh ra. Phan flng nay sinh ra 2 hoac 3 notron va toa nang lucmg khoang 200MeV dudi dang dpng nang cua eae hat.

GV yau cdu HS quan sat hinh 56.1 va md ta phan flng xay ra

221

thai khong ben va vd thanh hai hat nhan cd sd khdi trung binh theo phuong trinh phan flng :

1 , 2 3 5 T T ^ 2 3 6 T T o n + 92 U —>• 92 U

9 5 Y , I 3 8 T , o l

Hat nhan ytri 39Y phdng xa y va 1 TO

hat nhan iot 531 phan ra p


- Sau mdi phan flng ddu cd hon 2

notron dupc phdng ra, va mdi phan

bach deu giai phdng ra nang lupng

ldn.


Hoat ddng 3

Tim hieu phan flng phan hach

day chuyen


- Khi do su phan bach se tang rdt nhanh trong khoang thdi gian ngdn.


GV yau cdu HS nau cac dac diem ehung

ciaa phan flng phan bach

GV thdng bao

- Nang lupng dupc giai phdng trong phan flng phan bach gpi la nang lupng hat nhan.

GV nau cau hdi dd HS rim hidu phan

flng phan hach day chuyen

- Nhan xet gi vd sd phan hach xay ra tiep theo neu cac ncftron sinh ra cua phan bach ddu tian cua hat nhan urani (hoac plutoni...) dupe cac hat nhan urani (hoac plutoni...) d gdn hdp thu.

GV thdng bao

- Cac notron sinh ra sau mdi phan hach eua hat nhan urani (hoac plutoni...) dupc eae hat nhan urani (hoac plutoni...) d gdn hdp thu, va cfl the, sy phan hach tia'p didn thanh mpt day chuydn. Sd phan

222

HS thao luan ehung toan ldp - Mudn phan img phan hach day chuydn xay ra thi sd notron trung binh edn lai sau mdi phan hach phai ldn hon 1.


hach tang lan rdt nhanh trong mpt thdi gian ngdn, ta cd phan img phan hach day chuydn. GV yau cdu HS tim dieu kian dd xay ra phan img phan bach day chuyen

GV thdng bao - Tran thyc td, khdng phai mpi notron sinh ra deu cd thd gay ra sy phan bach, bdi vi ed nhidu notron bi mdt mat di do nhidu nguyan nhan khae nhau: bj hap thu bdi cac tap ehdt trong nhian lieu hat

nhan, hoac bj ^ Û hap thu ma khdng xay ra phan hach, hoac bay ra ngoai thd tich khdi urani (hoac plutoni...). Gpi k la sd notron tmng binh cdn lai sau mdi phan hach.

Ndu k < 1 thi phan img day chuyen khdng xay ra.

Ndu k = 1 thi phan flng day chuyen xay ra vdi mpt dp notron khdng ddi. Dd la phan flng day chuyen didu khidn dupc xay ra trong Id phan flng hat nhan.

Ndu k > 1 thi ddng notron tang lien tuc theo thdi gian, ddn tdi vu nd nguyan tfl. Dd la day chuydn khdng didu khidn dupc. - Dd giam thidu sd notron bi mdt vi thoat ra ngoai nham dam bao cd k > I, thi khdi lupng nhidn lieu hat nhan phai cd mpt gia trj tdi thidu, gpi la khdi lupng tdi

ban mth. Vdi ^ Û thi m^^^ vao cd 15

kg; vdi ^^^Pu thi m,h vao co 5kg.

223

Hoat ddng 4

Tim hieu Id phan flng hat nhan

va nha may dien hat nhan


- Cae phan img hat nhdn phai xay

ra dudi dang phan flng phan hach

day chuyen didu khidn dupe. Tfle

la phai duy tri cho k = 1.



- Bp phan chinh cua nha may dian

hat nhan la Id phan img hat nhan.

- Dung nang lupng hat nhSn dd

lam bdc hoi nudc, sau dd dung hoi

nudc dd lam quay tua bin cua may

phat dien.

GV neu eau hdi dd HS rim hidu Id phan

ihig hat nhan

- Trong thyc te, dd thyc hipn cac phan

img hat nhan hoac che tao nha may dien

hat nhan cdn mpt Id phan img hat nhan

dd thyc hian cae phan flng hat nhan. Di

Id phan flng boat dpng an toan thi cae

phan long hat nhan xay ra trong Id phai

thoa man dieu kien gi ?

GV kd chuyen Ijch sfl

- Ldn ddu tian, nang 1942, Fec-mi va

cac cpng sy cua dng da thyc hian thanh

cdng phan flng nay trong Id phan flng d

trudng dai hpc Si-ea-gd (My). Nhian

liau phan hach trong phdn ldn cac Id

phan flng la ^^Û hay ^^^Pu. Dd dam

bao cho k = 1, trong cac Id phan flng

ngudi ta dung eac thanh dieu khien cd

chfla bo hay cadimi, la cac chdt ed tac

dung hdp thu notron.

GV gidi thieu ve so dd Id va boat ddng

cua Id phan flng hat nhan tran hinh 56.3.

GV nau cau hdi dd HS rim hidu nha may

dien hat nhan

- Nha may dien sfl dung nang lupng hat

nhan dd chuyen thanh dien nang la nha

may dien hat nhan. Bp phan chinh cua

nha may dian hat nhan la gi ? Lam thd

nao de chuydn nang lupng hat nhan

thanh nang lupng dien ?

224

HS chii y quan sat va ldng nghe

Hoat ddng 5

Ciing cd bai hpc va dinh hudng

nhiem vu hpc tap tiep theo

GV gidi thiau nguyan tde boat dpng cua nha may dian hat nhdn tran hinh 56.4

- Chat tai nhiet so cap, sau khi chay qua vung tam Id, se chay qua bp trao ddi nhiet, cung cdp nhiat cho Id sinh hoi. Hoi nudc lam chay tua bin phat dien gidng nhu trong nha may dien thong thudng.

GV yau cdu HS lam cae bai tap trong

phia'u hpc tap de eung cd bai hpc

- HS vd nha lam cae bai tap 1, 2, 3, 4 SGK.

- On tap lai cac kidn thflc vd phan flng nhiet hach.

PHl£u HOC TAP

cau 1. Didu nao sau day sai khi ndi vd phan flng hat nhan phan hach ?

A. Phan flng hat nhan phan bach la phan irng toa nang lupng.

B. Phan ihig hat nhdn phan hach la hian tupng mpt hat nhah nang ha'p thu mpt ncftron cham rdi vd thanh hai hat nhan tmng binh.

C. Phan img hat nhan phan hach la hien tupng hai hat nhan nhe ket hpp lai thanh mpt hat nhan nang hon.

D. Phan img hat nhan phan hach cd thd kidm soat dupc.

cau 2. Didu kien dd xay ra phan img day chuydn la sd notron trung binh k cd gia tri

A. k > l . B. k< l .

C. k = l. D. k> l .

cau 3. Dieu nao sau day sai khi ndi vd phan flng day chuydn ?

A. Trong phan ung day chuydn, sd phan hach tang rdt nhanh trong thdi gian ngan.

B. Khi sd notron trung binh ldn hon I, con ngudi khdng the dieu khien dupe phan flng ddy ehuydn.

TKBGVLyi2/2(NC) 225

C. Phan img day chuydn luon xay ra khi cd mpt phan hach xay ra trong

khdi chat phdng xa ^H XJ.

D. Khi sd ncftron trung binh nhd ban 1, con ngudi ed the didu khidn dupc phan flng day chuyen.

cau 4. Didu nao sau day sai khi ndi ve nha may dien hat nhan ?

A. Trong Id phan flng eua nha may dien nguyan tfl, ngudi ta thuc hian phan flng nhiat hach dd cung cdp nang lupng cho nha mdy dien.

B. Ngudi ta didu khidn dupe phan flng day chuyen trong Id phan flng cua nha may dien hat nhan.

C. Cha't lam cham trong Id phan flng cd tac dung bien ncftron nhanh thanh ncftron cham.

D. Thanh didu khien ed tac dung didu chinh sd notron trung binh.

cau 5, Bp phan nao trong eae bp phan sau day khong ed trong Id phan ung hat nhan cua nha may dien hat nhan ?

A. Binh khi nhian liau chfla khi doteri.

B. Chdt lam cham.

C. Thanh didu khidn.

D. Thanh bao va phdng xa.

cau 6. Cho phan ihig phan hach : ^n + ^^|u-> fJSr+'^Xe + 2on + 185MeV.

Nang lupng toa ra khi 1kg %l\3 bi phan hach la

A.O,758.10'^J. B.l58.10'^J.

C.75,8.10'^J. D. 758.10^^1.

226

BAI57

P H A N ITNG NHlfiT H A C H

I-MUCTl£u

LVeki^n thflc

- Nau dupc phan flng nhiat hach la gi.

- Nau dupe dieu kien dd phan flng nhiat hach xay ra.

, - Nau dupe uu didm cua nang lupng do phan ihig nhiet bach toa ra.

2. Vi kl nang

- Ren luyan kT nang giai thieh cae hien tupng vat li.

- Ren luypn kT nang lam cae bai tap trdc nghiem khach quan nhidu lya chpn phdn phan flng nhiet hach.

- Ren luyen kT nang thu thap thdng tin khi dpc tai liau.

U-CHU1NBI

Gido vien

- Chudn bj phia'u hoc tap cho HS.

Hpc sinh

- On tap lai cac kidn thflc vd phan flng nhiet hach.

in - THife'T Kfi HOAT D 6 N G DAY HOC


Hoat ddng 1

Kiem tra, chuan bi dieu kien xuat phat HS suy nghT ca nhan tim cau tra ldi


GV ndu cau hdi kidm tra kien thflc cu - Lay mpt vi du vd phan flng phan hach va mpt vi du vd phan iing nhiet hach.

Dat vdn de : Ta da biet, khi hai hat nhan nhe hpp lai thanh hat nhan nang hon thi

227

HS nhan thflc dupc vdn dd cua bai hoc

cd nang lupng dupc toa ra. Lam thd nao de hai hat nhan nhe hpp lai dupc ? Bai hpc ngay hdm nay giup chflng ta tim hidu didu dd.

Hoat ddng 2

Tim hieu phan flng nhiet hach


- Vi cac hat nhan ddu la nhihig hat dian tich duong nan mudn hai hat nhan nhe cd thd hpp lai thanh hat nhan nang hon, ta phai cung cao cho ehung mpt dpng nang du ldn dd thang lye ddy Cu-ldng giua chflng, va ehung ridn lai gdn nhau de'n mflc ma lye hat nhan phat huy tac dung, lam ehung ket hpp vdi nhau.


GV nau cau hdi dd HS tim hidu phan flng nhiet bach - Vi du ta cd phan flng hat nhan :

]u+]U^lUe+ln lam the nao dd hai hat nhan doteri kdt hpp lai thanh hat nhan ball nhu phan img tren ?

GV nau eau hdi gpi y - Cac hat nhan mang dien tich gi ? Lye Cu-ldng gifla ehung la lye hut hay lye day? - Mudn chflng kdt hpp lai vdi nhau thi phai tdn tai lye gi ?

- Lye hat nhan chi xudt hian khi nao? Mudn vay cdn phai lam gi de lye hat nhan xuat hien ?

GV thdng bao - Phep tinh ehung td ring, mudn cd dupc dpng nang ldn nhu vay, khi doteri

phai cd nhiet dp cd 10^ K. Chinh vi su tdng hpp hat nhan chi xay ra d nhiat dp rdt cao nan phan img nay dupe gpi la phan flng nhiet hach.

- Ngoai didu kidn nhiat do cao, cdn phai thoa man hai dieu kien nfla de phan flng tdng hpp hat nhan cd the xay ra. Dd la : mat dp hat nhan n phai du ldn, ddng thdi thdi gian At duy tri nhiet dp cao cung phai du dai.

228


Hoat ddng 3

Tim hidu phan flng nhiet hach trong vu tru va tren Trai Dat

HS lam viae ea nhan tim eau tra ldi

- Phan flng nhiat hach xay ra trong long Mat Trdi va eac ngdi sao. Nhd cac phan flng nay ma Mat Trdi cd thd toa ra mpt lupng nang lupng ldn mpt each lian tuc qua rdt nhidu the ki ton tai ciaa loai ngudi.

- Tren Trai Ddt, con ngudi da thyc hien dupe phan flng nhiat bach dudi dang khdng kidm soat dupe. Dd la sy nd cua bao nhiat hach hach hay bom hidrd (hay cdn ed tan gpi khae la bom khinh khi).

- Hien nay, ngudi ta dang cd gang nghian eiiii dd kidm soat dupc cac phan ihig nhiat hach dd dam bao cung.cap nang lupng lau dai eho eon ngudi.

Hoat ddng 5

Cling cd bai hpc va dinh hudng


GV gidi thieu tham hai phan img nhiet hach dupc quan tam

^ H + ^ H ^ ^ H e + ^ n + 17,5MeV

5 L i + ^ H - > ^ H e + ^ H e + ^n + 15,lMeV

GV yeu cdu HS dpc mue 2 va mue 3 i SGK sau dd tra ldi cae cdu hdi sau de tim hieu yd phan flng nhiat hach trong mu tru va tren Trai Ddt

- Trong phan vu tru phan flng nhiat | bach xay ra d dau ? Chung cd tac dung nhu the nao ?

- Tran Trai Ddt, con ngudi da thyc hien dupc phan img nhiat hach chua? Phan ! ung nhiet hach da dupc kidm, soat de phuc vu ddi sdng san sudt eua con ngudi hay chua ?

GV yau cdu HS lam cae bai tap trong

. phia'u hpe tap dd cung ed bai hpc

: - HS vd nha lam cae bai tap 1, 2 SGK.

229

PHlfiu HOC T^P

cau 1. Ket luan nao trong cac kdt luan sau day sai khi ndi vd phan ling nhiat hach ?

A. Phan flng nhiet hach la phan flng toa nang lupng.

B. Phan flng nhipt hach chi xay ra d nhiet dp rdt cao.

C. Phan flng nhiet hach xay ra d nhiet dp cao nan goi la phan flng thu nang lupng.

D. Hien nay, con ngudi chua kidm soat dupc phan flng nhiet hach.

cau 2. Dieu kien dd phan flng hat nhan nhiet hach xay ra la

A. eac hat nhan nhe ban ddu phai d trong didu kien nhiet dp rdt cao.

B. sd notron tmng binh sinh ra phai ldn hon 1.

C. ban ddu phai cd 1 notron cham.

D. phai thyc hian phan flng trong ldng mat trdi hoac trong ldng cac ngdi sao.

Cau 3. Gpi Qi la nhiet lupng toa ra khi thyc hien phan flng nhiet bach eua m kg

nhien lieu nhiet hach, Q2 la nhiet lupng toa ra khi thyc hien phan flng phan

hach cua m kg nhian liau phan bach. Kdt luan nao sau day dflng khi so

sanh Qj va Q2 ?

A. Qi=Q2- B. Q,>Q2.

C. Qi<Q2. D. Q i = i Q 2 .

cau 4. Cho phan flng nhiet hach : ^H+ ^H -> 2He+ on + 17,5MeV Bidt ring

m^j, = 4,0015u. Nang lupng toa ra khi 1kg haii dupc tao thanh la

A. 26,3.l0^''MeV.

B.2,63.102'^MeV.

C. 263.10^'^MeV

D. 0,263.10^'^MeV.

230

CHUONG X. TLf VI MO DEN VI MO

BAI58

CACHATSOCAP

I - M U C T l £ u

l.ve'ki^nthfllc

- Ndm dupc khai niam hat so cdp, bia't mpt sd dac trung co ban eua hat so cdp;

- Trinh bay dupe sy phan loai cac hat so cdp. Nau dupc tan mpt sd hat so cdp.

- Hieu khai niem phan hat, hat quae va bidt tuong tac co ban gifla cae hat so cap.

2. va' ki nSng

- Ren luyen kT nang thu thap thdng tin khi dpc tai lipu.

- Ren luyan kT nang dn luyen kien thflc cu.

- Ren luyan kT nang lam bai tap trdc nghiam khach quan nhidu lya chpn phdn cae

hat so cdp.

II-CHUXNBI '

Gido vien

- Ve bang dac trung eua mpt sd hat so cdp tran gidy khd AQ.

- Chudn bi phidu hpc tap cho HS.

Hpc sinh

- On lai cac kidn thflc vd aiectron, phdtdn, notron, notrind vd cdu tao hat nhan.

Ill - THifiT K £ HOAT D O N G DAY HOC

Hoat ddng cua hpc sinh Trp giup cua giao vien

Hoat ddng 1

Kiem tra, chu^n bj dieu kien

xuat phat. Dat van dd

GV nau cau hdi kidm tra kie'n thflc cu

- Trong chuong trinh vat li phd thdng

231

HS suy nghT ca nhan rim cau tra ldi

HS nhan thflc dupc va'n dd eua bai hpc

Hoat ddng 2

Tim hieu cac dupc trung cua hat so ca'p



- Phdtdn va notrind cd khdi lupng bdng khong. Electron cd khdi

lupng nghi mo = 9,1.10"^' kg;

prdtdn cd khdi lupng nghi

mo = l,6726.lO"2^kg.

- Mpt sd hat so cdp cd dien tich bang dien tich nguyan td e, mpt sd hat khae cd dien tich bdng khdng.

da dupc hpc, em da bidt hat nao cd kich thude nhd hon kieh thude hat nhan ? Kd tan cae hat dd.

Ddt vdn de : Ta da bie't hat nhan dupc cdu tao bdi cac prdtdn va notron. Liau cac hat nay cd dupc cau tao tfl eae hat nhd hon hay khdng ? Gia thuydt cua Ghen-Man ma ehung ta hpe ngay hdm nay se giup chflng ta tra ldi cau hdi dd.

GV gidi thidu vd hat so cap

- Cho da'n nay, ngudi ta da phat hien dupc eac hat cd kich thude va khdi lupng rdt nhd, chang ban nhu aiectron, prdtdn, ncftron, mazdn, muydn, pidn. Tdt ca cac hat nay dupc gpi la cac hat so cap (hay eae hat co ban). Ndi ehung, hat so ca'p cd khdi lupng va kich thude nhd hon hat nhan nguyan tfl.

GV nau cau hdi de HS tim hidu cac dac trung cua hat so cdp

- Nau eac dac trung vd khdi lupng nghi va dian tich cua eac hat so cap ma em da bia't.

232



GV bd sung

- Thay cho m^ ngudi ta cdn thudng dCing

dai lupng dac trung la nang lupng nghi EQ

tinh theo he thflc Anh-xtanh EQ = moC .

Chang han electron cd khdi lupng nghi

mo-9,1.10"^*kg va Eo=0,511MeV;

prdtdn ed mg = 1,6726.10"^^ kg va

Eo=938,3MeV

- Hat so cdp ed thd ed dian tich Q = + I (tinh theo don vi do la dien tich nguyan td e), hoac Q = - 1 , hoac Q = 0. Q dupc

gpi la sd lupng tfl dien tich, bieu thi tinh gian doan cua dp ldn dien tich cae hat.

GV thdng bao

- Ngoai dac trung la khdi lupng nghi va dien tich, eac hat so cap cdn cd hai dac trung nfla la Spin va thdi gian sdng trung binh.

- Mdi hat so cdp cd momen dpng lupng riang va 'momen tfl riang dac trimg cho chuyen dpng ndi tai va ban chat cua hat. Momen nay dupc dac trung bang sd lupng tu spin, ki hieu la s. Momen dpng

lupng rieng cua hat bdng s — (h la 2jt

hdng sd Plang). Chdng ban, prdtdn va

ncftron cd spin s = —. nhu phdtdn cd

spin bang 1, pidn cd spin bdng 0.

- Trong sd eac hat so cdp, chi cd bdn

hat khdng phan ra thanh cac hat khae,

gpi la cac hat bdn (prdtdn, aiectron.

233

phdton, notrind). Tdt ea eae hat cdn lai la cae hat khdng bdn va phdn ra thdnh cdc hat khae. Trfl notron ed thdi gian sdng dai, khoang 932 s, cdn cae hat khong ben khae ddu cd thdi gian sdng

rdt ngan, ed tfl 10"^'*dah 10"^ s.

h

Hoat ddng 3

Tim hieu ve phan hat

HS lam viec ca nhan

- Phdn ldn cae hat so cdp ddu tao thanh cap, trong mdi cap cd hat va phan hat cua hat dd. Mdi cap gdm hai hat cd khdi lupng nghi mo nhu nhau, edn so dac tnmg khae thi cd trj sd bang nhau nhung trai dau. Vi du: aiectron va pdzitron cd eung khdi lupng nghi bang m . va spin

bang ~ . nhung cd dien tich tuong

ihig bang +1 va - 1 , tao thanh mpt cap.

- Trong qua trinh tuong tac eua eae hat so cap, ed thd xay ra hien tupng huy mpt cap "hat + phan hat" ed khdi lupng nghi khae khong thanh cac phdtdn, cung mpt slue sinh ra mpt cap "hat + phan hat" tfl nhihig photdn. Vi dung nhu qua trinh huy cap hoac sinh cap "aiectron + pdzitron":

e" + e" —> Y + Y

Y + Y -> e" + e"

GV yeu cdu HS dpc mue 3 SGK, sau dd tra ldi cau hdi dudi day de tim hidu vd fân hat

- Hat va phan hat gidng va khae nhau nhu the nao? Ldy vi du?

- Trinh bay hian tupng sinh mpt cap va buy mpt cap?

234

Hoat ddng 4

Tim hidu each phan loai hat so cap

HS lam viae ea nbdn

- Ngudi ta sdp xep eac hat so cdp

theo khdi lupng nghi mj, tang ddn.

Phdton ( lupng tfl anh sang) cd

m o = 0 .

Leptdn: gdm cae hat nhe nhu

aiectron, muydn (]x^,\x'), cae hat

tau ( T ' ' ' , T " ) . . .

Mazdn: gdm eae hat ed khdi

lupng trung binh trong

.khoang (200 ^900)mg, gdm hai

nhdm: mazdn n va mazdn K.

Bairon: gdm eac hat nang ed khdi lupng bdng hoac ldn hon khdi lupng cua prdtdn. Cd hai nhdm barion la nucldn va hiparon, cung Cdc phan hat cua chflng.

- Tdp hpp eae mazdn va cac barion cd tan ehung la eae hadrdn.

Hoat ddng 5

Tim hieu cac tuong tac cua cac hat so ca'p

HS lam viae ca nhan

- Tuong tac ha'p ddn : Dd la tuong tac gifla cac hat vat chdt cd khdi

GV yau cdu HS doc mue 4 SGK va tra ldi eau hdi sau day dd rim hidu each phan loai hat so cdp

- Ngudi ta can cfl vao dac trung nao dd phan loai cac hat so cap? Ngudi ta phan cac hat so cdp thanh nhflng loai nao?

-Hadrdn la gi?

GV yau cdu HS dpc mue 5 SGK va tra

ldi cdu hdi sau day de rim hidu cae

tuong tac cua cac hat so cdp

- Nau eac tuong tac co ban ddi vdi eac

hat so cap va eac dac didm cua cac

tuong tac dd?

235

lupng. Ban kinh tac dung eua lye ha'p ddn la vo cung. Cudng dp eua tuong tac ha'p ddn la nhd.

- Tuong tac dien tfl : Dd la tuong tac gifla cac hat mang dien, gifla eae vat tiep xue gay nan ma sat... Co cha' tucfng tac dien tfl la sy trao ddi phdton gifla cac hat mang dien. Ban kinh tac dung eua tuong tac dien la vd ban. Tuong tac dien tfl manh hon tuong tac ha'p din

khoang 10 lan.

- Tuong tac yeu : Dd la tuong tac

giua cac hat trong phan ra p .

Tuong tac yeu ed ban kinh tac

dung ed 10 m va cd cudng do

nhd hon tuong tac dien tfl khoang

10'^ldn.

- Tuong tac manh : Dd la tuong tac gifla cac hadrdn, nhu tuong tac gifla cae nucldn trong hat nhan, tao nen luc hat nhan, cung nhu tucfng tac ddn da'n sy sinh hat hadrdn trong cac qua trinh va cham cua cac hadrdn, tUong tac gifla cae hat quae. Ban kinh tac dung ed

10^'^m va ldn hon tuong tac dien tfl khoang 100 ldn.

Hoat ddng 6

Tim hieu ve hat quae

HS lam viec ca nhan

- Theo gia thuyet cua Ghen-Man :

GV yau cdu HS dpc mue 56SGK va tra ldi cau hdi sau day dd tim hieu vd hat quae

236

Ta't ea cac hadrdn ddu cau tao tfl eae hat nhd hcfn, gpi la quae. Cd 6 loai quae la u, d, s, c, b, va t, cung vdi 6 phan quae vc^ dien tich cd ddu ngupe lai. Cac hat quae da dupc quan sat thdy trong thi nghiam, nhung ddu d trang thai lian ka't; chua quan sat dupc eac hat quae ty do.

- Cae bairon la td hpp cua ba quae. Chang ban proton dupe tao ntn tfl ba quae (u, u, d), notron dupc tao nan tfl ba quae (u, d, d).

- Dien tich nguyen td e khdng phai' la nhd nhdt vi eae hat quae va phan

e 2e quae cd dien tich bang +—,+

- Thanh cong cua gia thuyet vd hat

quae la dy doan dupe sy tdn tai cua

hat dmaga trfl Q" (s, s, s), ma sau dd da tim ra dupc bdng thyc nghiem vdi ddy dia dac trung nhu dy doan.

Hoat ddng 7

Cung cd bai hpc va dinh hudng

nhiam vu hpc tap tiep theo

• '

- Kdt luan : Cac hat so cap la nhd nhat la dung hay sai ? Gia thuydt nao phu nhan ket luan tran ? Gia thuyet dd da dupc kiem tra bang thyc nghiem chua ?

- Dian tich nguyan td e la nhd nhdt khdng ? Tai sao ?

- Thanh cdng cua gia thuyet cua Ghen -

Man la'gi ?

GV yau cdu HS lam eac bai tap trac nghiem trong phieu hpc tap dd cung cd kia'n thflc da hpc.

- HS vd nha lam eac bai tap 1, 2 SGK.

- On lai cac kien thflc da bie't vd he Mat Trdi, Trai Ddt da hpc d ldp 10 THPT.

237

PHIEU HOC T^P

cau 1: De phan loai cac hat so ca'p, ngudi ta can cfl vao

A. dp ldn cua dian tich ciaa cac hat so cdp.

B. khdi lupng nghi cua eac hat so cap.

C. mdmen dpng lupng riang eua cae hat so ca'p.

D. thdi gian sdng trung binh cua eae hat so ca'p.

can 2: Ket luan nao sau day sai khi ndi vd spin cua hat so cap ?

A. Mdi hat so cdp ddu ed mdmen spin dac trung eho chuydn dpng npi tai cua nd.

B. Spin dupc dac trung bang sd lupng tfl spin, ki hieu la s.

C. Spin la mdmen dpng lupng riang cua hat so cdp.

D. Ta't ca eae hat so cap deu cd spin bang 1 hoac bang 0.

Can 3. Chpn phuong an dung.

Cd cac loai hat so cap nhu sau

A. photon ; leptdn ; mazdn ; barion.

B. phdtdn ; leptdn ; mazdn ; prdtdn.

C. phdtdn ; leptdn ; notron ; barion.

D. phdtdn ; electron ; mazdn ; barion.

cau 4: Cac hat so ca'p bdn la

A. proton ; aiectron ; phdtdn ; notron.

B. prdtdn ; aiectron ; phdtdn ; notrind.

C. prdtdn ; aiectron ; notron; notrind.

D. prdtdn ; notron; phdtdn ; notrind.

cau 5: Ket luan nao sau day sai khi ndi vd hat va phan hat ?

A. Hat va phan hat cd khdi lupng nghi gidng nhau.

B. Hat va phan hat cd spin nhu nhau.

C. Hat va phan hat cd eung dien tich.

D. Hat va phan hat cd ciing dp ldn dien ti'ch nhung khae nhau vd ddu.

cau 6: Ka't ludn nao sau day dung khi ndi vd hat va phan hat ?

Trong qua trinh tuong tac cua cac hat so cap, ed thd xay ra hien tupng

238

A. buy mpt cap 'hat + phan hat' ed khdi lupng nghi khae 0 thanh eac phdtdn hoac cflng mpt luc sinh ra mpt cap 'hat + phan hat' tfl nhihig phdtdn.

B. buy 'hat' va sinh phan hat'

C. buy 'phan hat' va sinh 'hat'

D. ehi sinh *phan hat'

cau 7: Thdi gian sdng trung binh cua hat nao sau day ldn nhdt ?

A. pidnTt''

B. dmaga Q"

C. ncftron.

D. notrind.

can 8: Cd cac loai tuong tac co ban ddi vdi cac hat so cdp la

A. tuong tac hdp ddn, tuong tac masat, tuong tac dien tfl, tuong tac dan hdi.

B. tuong tac hdp ddn, tuong lac Cu-ldng, tuong tac dien tfl, tuong tac masat.

C. tuong tac dian tfl, tuong tac hdp ddn, tuong tac manh, tuong tac ydu.

D. tuong tac dian tfl, tuong tac dan hdi, tuong tac manh, tuong tac yeu.

cau 9: Lye hat nhdn xudt hian trong tuong tac nao ?

A. Tuong tac yeu.

B. Tuong tac ha'p ddn.

C. Tuong tac manh.

D. Tuong tac dien tfl.

cau 10: Ka't luan nao sau day sai khi ndi vd eac hat quae ?

A. Cae hat quae nhd hon cae hat so cdp.

B. Dien tich eua cac hat quae nhd hon dien tich nguyan td e.

C. Cac hat quae chua dupc quan sat thdy trong thyc nghiam.

D. Hien nay, ngudi ta chua quan sat dupe eae hat quae ty do.

239

BAI59

M A T TRCJI. Hfe MAT TRCn

I-MUCTlfiU

1. Ve kie'n thflc

- Bia't cdu tao he Mat Trdi, cac thanh phdn cau tao he Mat Trdi. - Hieu eac dac didm chinh cua Mat Ttdi, Trai Dat va Mat Trang. - Neu dupe dac diem ehinh eua he Mat Trdi.

2. Va' ki nang

- Ren luyen kT nang giai thich cac hien tucmg vat li. - Ren luyan kT nang thu thap thdng tin khi dpc tai liau. - Ren luyen kT nang dn luyen kie'n thflc cu. - Ren luyen kT nang lam bai tap trac nghiem khach quan nhidu lya chpn phdn ha mat trdi.

II-CHUXNBI

Gido vien


- Ve hinh 59.1 SGK tren giay kho AQ.

- Suu tdm cac anh ve Mat Trdi, Trai Ddt, Mat Trang va sao chdi.

Hpc sinh

- On lai cac kien thflc da bie't vd he Mat Trdi, Trai Ddt da hpc d ldp 10 THPT.

Ill - THlfiT K£' H O A T D 6 N G D A Y HOC


Hoat ddng 1


HS suy nghl ca nhan rim cau tra ldi


GV neu cau hdi kiem tra kien thflc cu

- Phat bidu ba dinh luat Ke-pla ?

240

HS nhan thflc dupc vdn dd cfla bai hpc

Hoat ddng 2

Tim hieu ve ca'u tao va chuyen ddng cua he Mat Trdi


- Mat Trdi d trung tam cua He.

- Cd tam hanh tinh ldn chuyen dpng quanh Mat Trdi: Thuy tinh (edn gpi la sao thuy), Kim tinh (Sao Kun), Trai Ddt, Hoa tinh, Mdc tinh (Sao Mdc), Thd tinh (Sao Thd), Thian Vuong tinh (hay Thian tinh) va Hai Vuong tinh (hay Hai tinh).

HS ua'p thu, ghi nhd

Ddt vdn de : Ngay nay, nhd cac kinh thian van hien dai, eac con tau va tram vu try, con ngudi sdng tran Trai Ddt da ed dupc nhung hidu biet ngay cang day du, sau sdc vd ha Mat Trdi cua ehung ta. Nhung kien thflc trong bai hpc nay la ket qua cua nhung nghian cflu nhd cdc thia't bj tran.

GV nau cau hdi dd HS tim hidu cdu tao va chuyen dpng cua he Mat Trdi

- Theo thuydt nhat tam cua Cd-pec-nic thi Mat Trdi ddng vai trd la gi eua he ?

- Kd tan cac hanh tinh ldn ehuydn dpng quanh Mat Trdi ?

GV thdng bao

- Dd do khoang each tfl eac hanh tinh den Mat Trdi, ngudi ta dung don vi thian van (ki bifu dvtv). 1 dvtv bang khoang each tfl Trai Ddt ddn Mat Trdi, xdp xi bang 150 trieu kildmet.

- Didu dang chu y la tdt ca cac hanh tinh ddu chuyen dpng quanh Mat Trdi theo cung mpt chidu (chidu thuan), va gdn nhu trong eung mpt mat phang. Mat Trdi va cae hanh tinh ddu quay quanh minh nd va ddu quay theo chidu thuan

TKBG VL^l 2/2 If^ 241

—

Hoat ddng 3

Tim hieu ve Mat Trdi HS lam viec ca nhdn - Mat Trdi cS u tao gdm hai phdn la quang cdu va khi quydn.

Quang cdu : Nhin tfl Trai Ddt ta thdy Mat Trdi cd dang mpt dia sang trdn vdi ban kinh gde 16 phut. Khdi cdu ndng sang nhin tha'y nay dupe gpi la quang cdu. Khdi lupng riang trung binh cua vat ehdt trong quang cdu la

1400kg/m^ Nhiat dp hieu dung d quang cdu cd 6000K, cdn nhiet dp trong long mat trdi vao cd tran chuc triau dp.

Khi quydn Mat Trdi : La ldp khi (ehu yeu la khi hidrd) bao quanh Mat Trdi. Khi quydn dupc phan ra hai ldp cd tinh chat vat li khae nhau la sac cdu va nhdt hoa.

Sdc cdu la ldp khi ndm sat mat quang cdu cd dp day tran 10000km va cd nhiat dp cd 4500K.

•

(trfl Kim tmh). Toan bd ha Mat Trdi quanh quanh trung tam Thian Ha eua chflng ta. - Bidt chu ki va ban true ldn eua quy dao cua eac hanh tinh (xac dinh bang phuong phap thian van do ludng) tfl djnh luat ni Ka-ple ngudi ta da tim thdy khdi lupng cua Mat Trdi ldn hcfn khdi lupng eua Trai Daft 333 000 ldn, tfle la

bang 1,99. lO^^kg.

GV yau cdu HS dpc mue 2 SGK va tra ldi eae cau hdi sau day dd tim hidu vd Mat Trdi. - Nau cdu true cua Mat Trdi ?

242

Phia ngoai sdc cdu la nhat hoa. Vat chat cdu tao nhat hoa d trang thai ion hoa manh, nhiat dp khoang 1 trieu dp. Nhat hoa ed hinh dang thay ddi theo thdi gian.

- Hang sd Mat Trdi H la lupng nSng lupng bfle xa cua Mat Trdi truydn vudng gde tdi mpt don vj dian tich each nd mpt don vj thian van trong mpt don vi thdi gian. H cd tri sd nhu nhau khi dd d cac dai vat ll dja cdu, tran cac tram vu try ngoai khi quydn va cd trj sd :

H = 1360W/m^

- Cdng sudt bfle xa nang lupng cua

Mat Trdi la: ^ = 3,9.10^^ W.

- Vi trong long Mat Trdi dang dian ra eae phan iing nhiat hach.

- va't den cd mau sdm tdi, niet dp eua vdt den khoang 4000K.

- Nam Mat Trdi ed nhidu vdt den nha't xudt hipn dupe gpi la Nam Mat Trdi boat dpng. Nam Mat Trdi ed It vet den xua't hipn nhdt gpi la Nam Mat Trdi tinh. Chu ki boat dpng cua Mat Trdi ed tri sd trung binh la 11 nam.

- Hdng sd Mat Trdi H la gi ? H cd dac didm gi ? Cdng sudt bfle xa nang lupng Mat Trdi bdng bao nhiau ?

- Giai thich tai sao ka't qua do hang sd Mat Trdi tfl nhidu nam nay tha'y tri sd H khdng thay ddi theo thdi giwi ?

- Dac didm eua vdt den.

- Can cfl vao ddu hieu nao dd biet nam Mat Trdi boat dpng, n&n Mat Trdi tmh ? Chu ki boat dpng cua mat trdi la bao ifliiau nam ?

Hoat ddng 4

Tim hi u v^ Trai Dat va Mat Trang HS nhd lai kiah thflc da hpe trong chuong tiinh dia U ldp 10.

Giao vian nau cau hoi dd HS rim hidu vd Trai DSit.

- Trai Ddt chuyen ddng nhu thd nao ?

243

- Trai Ddt chuydn dpng quanh Mat Trdi theo mpt quy dao gdn trdn. True quay cua Trai Dat quanh minh nd nghiang tran mat phdng quy dao

mdtgdc23°27'

- Trai Ddt ed dang hinh phdng cdu (hoi det d hai eye), ban kinh d xieb dao bang 6378km, ban kinh d hai eye bang 6357km. Khdi lupng riang

tmng bmh la 5520km/m^

- Trai Ddt ed cdu tao bdi ba ldp: Ldp trong eimg la ldi Trai Ddt ed ban kinh khoang 3(X)0km, ed eau tao chu ya'u la sdt va niken. Bao quanh loi la ldp tmng gian va ngoai cung la ldp vd day khoang 35km dupe cdu tao chu ydu la da granit.


- Mat Trang each Trai Ddt 384000km cd ban kihh 1738km, cd

khdi lupng 7,35.10^^ kg. Mat Trang chuyen dpng quanh Trai Ddt vdi ehu ki 27,32 ngay.

- Vl trong khi ehuydn dpng quanh Trai Ddt, Mat Trang cdn tfl quay quanh true eua nd vdi chu ki dung bang chu ki chuydn ddng quanh Trai Ddt.

- Trai Ddt ed cdu tao nhu the nao ?

- Neu nhflng hieu biet eua em vd Mat Trang ?

- Tai sao khi Mat Trang ehuydn dpng quanh Trai Ddt thi nd ludn hudng mpt nfla nhdt dinh eua nd vd phia Trai Ddt ?

Hoat ddng 5

Tim hieu cac hanh Unh khae, sao chdi va ca thien thach


GV gidi thiau vd cae dac trung ehinh cua cae hanh tmh tran bang 59.1 SGK.

244

HS lam viae ca nhan

- Cae sao chdi cd kich thude va khdi lupng nhd chuydn dpng quanh Mat Trdi theo nhimg quy dao eUp rdt det. Sao chdi dupc cdu tao bdi eae chat da bde boi.

- Thian thach la nhihig khdi da chuydn dpng quanh Mat Trdi vdi tde dp tdi hang chuc kildmet tran giay.theo cae quy dao rdt khae nhau. Sao bang la nhimg thian thach chju lye hut eua Trai Ddt nen bay vao Trai Ddt, ma sat vdi khi quydn va bi bde chay.

Hoat ddng 6


GV yau cdu HS dpc mue 4 SGK va tra ldi cac eau hdi sau dd tim hidu vd sao chdi va thian thach

- Nau cac dac didm ehinh cua sao chdi va thian thach.

GV yau cdu HS lam cac bai tap trdc nghiam trong phidu hpc tap de cung cd kia'n thflc da hpc.

- HS vd nha lam cae bai tap 1, 2 SGK.

- On lai bai 59 va suu tdm cac tu lipu vd thian van hpc tren mang intemet.

PHIÛ HOC T^P

cau 1: Phat bieu nao sau day dung khi ndi vd cdu true cua Mat Trdi ?

Mat Trdi ca'u tao gdm hai phdn la

A. sdc cdu va nhat hoa.

B. quang eau va khi quydn Mat Trdi.

C. sdc cdu va khi quyen Mat Trdi.

D. quang cdu va nhat hoa.

245

cau 2: Quang cdu la

A. khdi cdu ndng sang khi nhin Mat Trdi tfl Trai Ddt.

B. khdi khi quydn bao quanh Mat Trdi.

C. ldp sdc cdu.

D. ldp nhat hoa.

cau 3: Mat Trdi duy tri dupc nang lupng bfle xa eua minh la do

A. kich thude cua Mat Trdi rat ldn.

B. mat Trdi cd khdi lupng ldn.

C. mat Trdi lian tiic ha'p thy nang lupng d xung quanh.

D. trong long Mat Trdi dang didn ra phan flng nhiet hach.

cau 4: Ka't luan nao sau day sai khi ndi vd sy chuyen dpng eua Trai Dat ?

A. Trai Ddt chuyen dpng quanh Mat Trdi theo mpt quy dao gdn trdn.

B. Trai Ddt tu quay quanh minh nd.

C. Trong qua trinh ehuydn dpng quanh Mat Trdi, Trai Ddt chuydn dpng quay quanh Mat TrSng.

D. True quay eua Trai Ddt quanh minh nd nghiang tran mat phang quy

daomptg6c23°27'

Cau 5: Phat bidu nao sau day sai khi ndi ve cdu tao cua Trai Ddt ?

A. Trai Dat cd dang hinh cdu hoi det d hai eye.

B. Ban kinh cua Trai Ddt d xich dao ldn hon ban kinh cua Trai Ddt d hai cue.

C. Ban kinh cua Trai Dat bing nhau d mpi vi tri.

D. Trai Dat cd mot cai ldi dupc cdu tao chu yeu la sdt va niken,

cau 6: Chpn phuong an dung.

Anh hudng ro rat nha't cua Mat Trang lan Trai Da't la

A. hian tupng thuy tridu.

B. hien lupng bao tfl.

C. hipn tupng xa mac hoa.

D. hian tupng han ban keo dai.

Cau 7: Chpn phuong an dung.

Mat Trang ludn hudng mdt nfla nha't dinh eua nd ve phia Trdi Da't vi

246

A. Mat Trang ty quay quanh true cua nd vdi chu ki bang chu ki ehuydn dpng quanh Trai Ddt.

B. Mat Trang each Trai Ddt 384000km.

C. Lye hdp ddn cua Mat Trang nhd.

D. Nhiat dp trong mdt ngay dam tran Mat Trang chanh lach nhau rdt ldn.

cau 8: Phat bieu nao sau ddy dung khi ndi ve sao chdi ?

A. Sao chdi la loai hanh tinh gidng nhu Trai Ddt.

B. Sao chdi cd kieh thude ldn hon kieh thudc Trai Ddt nhung nhd hon kich thude cfla Mat Trdi.

C. Chu ki chuydn dpng cua sao chdi quanh Mat Trdi bang chu ki chuydn dpng eua Trai Ddt.

D. Sao chdi cd kich thudc nhd va duoc cdu tao bdi eae ehdt dd bdc hoi.

247

BAI60

SAO.THlfiNHA

I-MUCTlfiU

1. va' kia'n thflc

- Bia't phan biet sao, hanh tinh, thian ha, nhdm thian ha.

- Bidt so bp phan biat eae loai thian ha.

- Bia't mpt vdi dac didm cua Thian Ha cua ehung ta. - Nau dupc mpt sd net khai quat vd sy tien hda cua cae sao.

2. Vi kl nSng

- Ren luypn kT nang giai thieh cae hien tupng vat li.

- Ren luyen kT nang thu thap thdng tin khi dpc tai liau. - Ren luyen kT nang lam bai tap trdc nghiem khach quan nhidu lya chpn phdn sao, thian ha.

II-CHUXNBI

Gido vien

- Sim tdm mpt sd anh chup ve thian ha.

- Chudn bj phia'u hpe tap eho HS.

Hpc sinh

- 6n lai bai 59 va sim tdm cae tu lieu ve thian van hpc tran mang intemet.

m - THlfiT K£' HOAT D 6 N G DAY HOC


Hoat dong 1


HS suy nghT ca nhan tim eau tra ldi


GV neu eau hdi kidm tra kien thflc cu - Ha Mat Trdi bao gdm nhung loai thian thd nao ?

248

HS nhan thflc dupc vdn di eua bai hoe

Ddt vdn de : Ngdm nhin bdu trdi ban dam vdi dai Ngan Ha md ao, nhflng ngdi sao ldp lanh, ta ed thd dat ra bidt bao eau hdi : "Cae sao ed gi khae biat nhau ?", "Liau quanh mdi sao cd cae hanh tinh chuydn dpng?", "Dai Ngan Ha md ao ed bao n^ iau sao ?"... Bai hpc ngay hdm nay giup ehung ta tra ldi eau hdi dd.

Hoat ddng 2

Tim hieu ve sao va su tien hoa cac sao

HS lam viae ca nhan

- Sao la mdt khdi khi ndng sang, gidng nhu Mat Trdi. Vi eac sao d xa nan ta thdy chflng nhu nhihig diem sang.

- Xung quanh mdt sd sao cd cae hanh tinh chuydn dpng nhu.

~ Khdi lupng cua eac sao cd gia trj ndm trong khoang tfl 0,1 lan khdi lupng Mat Trdi den vai chuc ldn khdi lupng Mat Trdi. Ban kinh eua eac sao ed gia tri ndm trong khoang tfl, mpt phdn nghin ldn ban kinh Mat Trdi ddn gap hang nghin ldn ban kinh Mat Trdi.

- Sao bia'n quang la sao cd dp sang thay ddi. Do la sao bien quang do che khuat va sao bien quang do nen dan.

- Sao mdi la sao ed dp sang tang dot ngpt lan hang ngan, ban van Idn, hoac hang tripu lan, sau dd tfl tfl giam.

GV yau cdu HS doc mue 1 va 2 SGK sau dd tra ldi cae cau hdi sau de tim hidu vd sao.

- Sao gidng each hanh tinh chuyen dpng quanh Mat Trdi hay gidng Mat Trdi ? Tai sao chflng ta nhin thay cac ngdi sao chi nhd nhu nhflng'didm sang ?

- Xung quanh eae sao cd cac hanh tinh chuydn dpng khdng ?

- Kich thudc va khdi lupng cua cac sao.

- Nau cac dac diem cua cae loai sao dac biat.

TKBGVLyi2/2(NC) 249

- Punxa, sao notron la sao bfle xa nang lupng dudi dang nhflng xung sdng dien tfl rdt manh.

- L6 den la mpt thian the dupe rian doan bdi li thuydt, cung dupc cdu tao bdi eae ncftron, cd trudng hdp ddn ldn den ndi thu hut mpi vat thd, ke ca anh sang! Vi vay, thian the nao tdi den, khdng phat xa bdt ki sdng dien tfl nao. Ngudi ta ehi phat hien dupe mpt 16 den nhd tia X phat ra, khi 16 den dd hut mpt thian thd gdn dd.

- Tinh vdn la nhihig dam bui khdng Id dupc rpi sang bdi cac ngdi sao d gdn dd, hoac la cae dam khi bj ion boa dupc phdng ra tfl mpt sao mdi hay sao siau mdi.


- Lo den la gi ? Tinh van la gi ?

GV trinh bay vd sy tien hoa cua cac sao - Cac sao dupe cdu tao tfl mpt dam may khi va bui. Dam may nay vfla quay vfla CO lai do tac dung eua lye hdp ddn va sau vai chuc nghin nam, vat ehdt ddn ddn tap trung d gifla, tao thanh mpt tinh van day dac va det nhu mpt cae banh day. O trung tam tinh van, noi mat dp cao nhdt, mpt ngdi sao nguyan thuy dupc tao thanh. Vi mdi ra ddi, sao chua ndng lan chi phat ra bfle xa d midn hdng ngoai. Sao lai tiep tuc co lai va ndng ddn va trd thanh ngdi sao sang td.

— Trong trudng hpp sao la Mat Trdi thi vat chat d phia ngoai dam bui khi ngung tu va dpng lai thanh mpt vanh dai, ndi nhimg hanh tinh se dupe ta ra va quay xung quanh Mat Trdi.

250

- Khi nhian Ueu trong sao can kiel, sao bien thanh cae thian the khae. Vi du: Ddi vdi eac sao ed khdi lupng ldn hon Mat Trdi tfl nam ldn trd ldn chi sdng dupc khoang 100 trieu nam, nhipt dp ciaa sao giam dan va sao trd thanh sao kenh dd, sau dd sao tidp tuc tidn hoa va trd thdnh mdt sao notron hoac mdt 16 den.

Hoat ddng 3

Tim hieu ve thien ha

HS lam viec ca nhan

- Cac sao tdn tai trong vu try thanh nhflng he thdng tucfng ddi dpc lap vdi nhau. Ha thdng sao gdm nhieu loai sao va tinh van gpi la thian ha.

- Cd ba loai thian ha chinh :

Thian ha ed hinh dang det nhu

cai dia cd nhflng canh tay xodn de, chfla nhieu khi, gpi la thian ha xoan de.

Thian ha hinh clip, chfla it khi va

cd khdi lupng trai ra tran mdt dai

rdng, gpi la thian ha clip.

Thian ha khdng cd hinh dang xae djnh, trdng gidng nhU nhflng dam may, gpi la thien ha khdng djnh hinh.

- Tliian Ha cua ehung ta la loai thian ha xodn de, cd dudng kinh khoang 100 nghin nam anh sang va cd khdi lupng bang khoang 150 ti ldn khdi lupng cua Mat Trdi.

- Thian Ha cua ehung ta la mpt ha phang gidng nhu cai dia, day khoang

GV yau cdu HS dpc mue 4 SGK sau dd

tra ldi eac cdu hdi de tim hidu vd thian ha.

- Thian ha la gi ? Cd mdy loai thian ha ?

Nau dac didm eua eac loai tbidn ha dd.

- Thian Ha eua chflng ta thupc loai thian ha nao ? Kich thude va khdi lupng eua nd bang bao nhiau ? Nau ca'u tao eua Thian Ha eua chflng ta.

251

330 nam anh sang, chfla vai tram ri ngdi sao. Hp Mat Trdi cua ehung ta ndm trong mpt canh tay xodn d ria Thian Ha, each tmng tam tran 30 nghin nam anh sang va quay quanh tdm Thian Ha vdi tde dp khoang 250km/s. Gifla ea sao cd bui va khi. Phdn trung tdm Thian Ha cd dang hinh cdu det, gpi la vung ldi trung tam, dupc tao bdi cac sao gia, khi va bui.

- Tfl Trai Ddt, ehung ta chi nhin dupe hinh chidu cua Thian Ha tran vdm trdi, nhu mpt dai sang trai ra tran bdu trdi dam, thudng dupc goi la dai Ngan Ha.

- Trong vu try ed hang tram ti thian ha, eac thian ha thudng each nhau khoang mudi ldn kieh thudc cua ehung ta. Cac tbidn ha cd xu hudng hpp lai vdi nhau thanh nhdm thian ha gdm tfl vai chuc den vai tram nghin thian ha.

- Cac nhdm thian ha lai tap hpp thanh siau nhdm thian ha hay dai thien ha.

Hoat ddng 5

Cung cd bai hpc va dinh hudng


~ Dai ngan ha la gi ?

~ Nhdm thian ha la gi ? Siau nhdm thian ha la gi ?

GV yau cdu HS lam cae bai tap trdc

nghiam trong phieu hpe tap de ciang cd

kien thflc da hpe.

- HS vd nha lam cae bai tap 1,2 SGK.

- On lai kia'n thflc vd hat so cdp va hiau img Ddp-ple.

252

PHlfiu HOC TAP

Cau 1: Sao mdi la sao ed

A. khdi lupng tang dpt ngpt len rdt nhidu ldn.

B. nhiat do giam xudng nhidu ldn.

C. the tich giam xudng nhieu ldn.

D. dp sang tang dpt ngdt lan nhidu ldn.

cau 2: Sao bidn quang la

A. sao cd dp sang thay ddi.

B. sao cd dp sang khdng ddi.

C. sao cd khdi lupng thay ddi.

D. sao cd khdi lupng khdng ddi.

cau 3: Phat bidu nao trong cae phat bidu sau ddy sai khi ndi vd tinh van ?

A. Tinh van la dam byi khdng Id dupc rpi sang bdi cac ngdi sao gdn dd.

B. Tinh van la eae dam khi bj ion boa dupe phdng ra tfl mpt ngdi sao mdi.

C. Tinh van la he thdng khong 16 cac sao.

D. Tinh van la cac dam khi bj ion boa dupc phdng ra tfl mpt ng6i sao siau mdi.

cau 4: Ket Iuan nao sau day sai khi ndi vd 16 den.

A. L6 den la mpt thian thd dupe phat hipn nhd quan sat qua kinh thian van.

B. Ld den cd trudng hdp ddn rdt ldn.

C. Thien thd dupc gpi la 16 den kh6ng phat xa ra ba't ki mpt loai sdng dien tfl nao.

D. Ngudi ta phat hien ra 16 den nhd tia X phat ra khi Id den hut mpt thian thd gdn dd.

cau 5: Thian ha dupe cdu tao tfl

A. ha thdng nhidu loai sao.

B. ha thdng nhidu loai hanh rinh.

C. ha thdng nhieu tinh ^ n .

D. ha thdng gdm nhidu loai sao va tinh van.

cau 6: Thian Ha eua chiing ta

A. cd dang xodn dc.

253

B. cd dudng kinh khoang 100 nghin nam anh sang.

C. ed ha Mat Trdi la trung tam.

D. cd khdi lupng bang khoang 150 ti ldn khdi lupng Mat Trdi.

cau 7: Dai ngan ha la

A. hinh chieu cua Thian Ha tran vdm trdi dupc nhin tfl Trai Dat.

B. hinh chidu eua Thidn Ha tran vdm trdi dupc nhin tfl Mat Trang.

C. hinh chieu eua Thian Ha tran vdm trdi dupc nhin tfl Mat Trdi.

D. hinh chieu eua Thian Ha tran vdm trdi duoc nhin tfl sao Hoa.

254

BAI61

THUYDT BIG BANG

I-MUCTl£U

1. Va' kia'n thflc

- Hidu cac sy kien ddn den sy ra ddi cua thuyet Big Bang.

- Nau dupc nhflng npi dung ehinh eua thuyet Big Bang.

2. Vi ki nang

- Ren luyan kT nang thu thap th6ng rin khi dpc tai liau. - Ren luyan kT nang dn luyan kidn thflc cu. - Ren luyen kT nang lam bai tap trdc nghiam khach quan nhieu lya chpn phdn thuyet Big Bang.

I I -CHUXNBI

Gido vien

- Chudn bi phieu hpe tap cho HS.

Hpc sinh

- 6n lai kidn thflc vd hat so cap va hieu flng Ddp - pie.

Ill - THlfiT K £ H O A T D 6 N G DAY HOC

Hoat ddng ciia hpc sinh

Hoat ddng 1

Kiem tra, chuan bi dieu kian xua't phat. Dat van de HS suy nghl ca nhan rim cau tra ldi

Trp giiip cua giao vi§n

GV nau eau hdi kidm tra kia'n thflc cu

- Thien ha la gi ? Nhdm thian ha la gi ?

Ddt vdn de : Vu try tfl dau sinh ra, sinh ra tfl bao gid, tidn hoa ra sao ?... Cac cau hdi nay dang ddn ddn dupc Thian

255

HS nhan thflc dupc vdn dd cua bai hoe

van hpc ngay nay tra ldi. Trong vai chuc nam gan day, ket hpp vdi thanh tyu eua vat li hpe hat so cdp. Vat li thian van da dat dupc mpt budc tidn quan trpng trong viec nghian ciru ngudn gde va sy tien boa cua vu tru. Dd la sy ra ddi eua thuyet Big Bang. Ndi dung ciaa thuydt Big Bang se dupc ehung ta tim hidu trong bai hpe ngay hdm nay.

Hoat ddng 2

Tim hieu cac thuyet ve su tie'n hoa vu tru


GV trinh bay cae thuyet ve sy tien hod vutru

- Khi nghian cihi ngudn gde va sy tien boa eua vu try, da cd hai trudng phai khae nhau.

Mpt trudng phai do nha vdt li ngudi anh Hoi-lo khdi xudng, eho rdng vu tru d trong trang thai dn dinh, vd thuy vd ehung, khdng thay ddi tfl qua khfl den tuong lai. vat eha't dupe tao ra mpt each lian tuc.

Trudng phai khae lai cho rdng vu try dupc tao ra bdi mpt vu nd eye ldn, eye manh each day khoang 14 ri nam, hian nay dang tidp tuc dan nd va loang ddn. Vu nd nguyen thuy nay dupe dat tan Id Big Bang.

Nam 1948, cac cdng trinh nghien cflu li thuyet eua nha vat li ngudi MT gde Nga Ga-mdp da tian doan vdt tich cua bfle xa vu try nguyan thuy, luc dau ndng il nha't hang triau ti dp, ngay cang ngupi ddn vi vu tru dan nd.

256

Hoat ddng 3

Tim hieu cac su kien thien van quan trpng

HS lam viae ca nhan

- Nhd eae quan sat thian van, ngudi ta phat hian ra sd cac thian ha trong qua khfl nhidu hon hien nay.

- Nam 1929, nha thien van hpc ngudi MT Hdp-bon, dya vao hieu flng Ddp-ple da phat hian thdy rdng, cac thian ha xa xam rai rac khdp bdu trdi ddu chay ra xa he Mat Trdi cua chflng ta. Tde dp chay ra xa cua thidn ha ri la vdi khoang each d gifla thian ha va ehung ta theo dinh luat Hdp-bon :

v = Hd

H gpi la hang sd Hop-bon cd trj sd

H = 1,7.10 m/(s.nam anh sang).

1 nam anh sang = 9,46. lO'^ km.

- Nam 1965, hai nha vat li thian van ngudi MT, Pen-di-at va Uyn-xon da tinh ed phat hian ra mpt bfle xa la khi hp dang thfl may thu tin hipu trdn bude sdng 3 cm. Sau dd, hpe da khang djnh dupc rdng, bfle xa nay dupc phat ddng ddu tfl phia trong khdng trung va tuong ihig vdi bfle xa phat ra tfl vat cd nhiet dp 3K. Bfle xa nay gpi la bfle xa ndn vu tru.

GV yau cdu HS dpc mue 2 SGK sau do tra ldi eac cau hdi sau de tim hidu cac sy kian thian van quan trpng

- Trinh bay cac sy kien thian van quan trpng. Tfl dd, cho biet trong hai thuyet vd sy rien boa vu try, thuyet nao dung.

257

- Hai su kian quan trpng tran da phu nhan trudng phai cho ring vu try d trong trang thai dn djnh va da minh chflng eho tinh dung dan cua thuyet Big Bang.

- Mpt ngudn sang phat ra mpt bfle xa don sdc budc sdng X, chuydn dpng vdi tde dp u ddi vdi may thu thi bude sdng bfle xa ma may thu nhan dupc se thay ddi mpt lupng

A 1

AX,, vdi -— = —, vdi u > 0 ndu X c

ngudn ra xa may thu, va u < 0 neu ngudn lai gdn may thu.

Hoat ddng 4 Tim hieu thuyet Big Bang

HS lam viae ca n h ^

- Sau vu nd ldn tp = 10"''^s (thdi

didm Plang) kich thudc vu try la

lO' -' m, nhiet do la lO^^K va

khdi lupng riang la 10^' kg/cm^

- Cae nucldn dupc tao ra sau vu nd mpt giay. - Ba phut sau vu nd xuat hien cac hat nhan nguyan tfl ddu tian. - Ba nghin nam sau mdi xuat hien cac nguyan tfl ddu tian. - Ba trieu nam sau mdi xudt hien cac sao va thian ha. - Tai thdi diem t = 14 ti nam, vu tru d trang thai hian nay, vdi nhiat do trung binh T = 2,7K.

- Npi dung hiau flng Ddp-ple vdi anh sang.

GV yau cdu HS dpc mue 3 SGK sau dd tra ldi cac cau hdi sau dd tim hidu thuyet Big Bang. - Hay tdm tat npi dung thuydt Big Bang.

258


Hoat ddng 5

Cung cd b i hpc va dinh hudng nhiem vu hpc tap tiep theo

GV bd sung - Nhihig sy kian va nhflng sd lieu da neu d tran day chua phai la hoan toan ehinh xae, edn ed nhflng ehd se phai bo sung hoac hieu ehinh. Tuy nhian, vd dai the, qua trinh tren day dupe coi la dang tin cay.

- Thuyet Big Bang chua giai thich dupe het cac sy kien quan trpng trong vu try va dang dupc cae nha vat li thian van phat tridn va bd sung.

GV yau cau HS lam cac bai tap trdc nghiam trong phidu hpc tap de eijng cd kia'n thflc da hpc. - HS vd nha lam cac bai tap 1, 2 SGK.

PHlfo HOC T^P

CAu 1: Cdng thflc bidu didn tde dp lui ra xa eua thian ha la

H A. V - B. v = Hd.

c.v=A H

D. v = HVd.

cau 2: Bfle xa nen vu try cd budc sdng

A. 3mm. ' B. 3cm.

C. 3dm. D. 3m.

C&u 3: Hai sy kien thian van quan trpng la vu try dan nd va bfle xa ndn vu try

da minh chflng eho tinh dung dan ciaa thuyet nao trong cae thuyat sau day ?

A. Thuydt aiectron.

B. Thuyet dian li.

C. Thuyet Big Bang.

D. Thuydt dpng hpe phan tfl chdt khi.

259

CSu 4: Phat bidu nao sau day sai khi ndi vd thuydt Big Bang ?

A. Theo thuyet Big Bang, vu try tao ra bdi mpt vu nd ldn.

B. Hien nay, vu try dang nd ra va loang ddn.

C. Hien nay, vu tru dang co lai.

D. Vu nd Big Bang each day 14 ti nam.

260

MUCLUC

Trang

CHUONG V. DONG Dl|N XOAY CHliu 3

Bai 26. Ddng dien xoay chieu. Mach dien xoay chieu chi c6 di§n trd thuan 3

6a/ 27. Mach dien xoay chieu chi co tu dien, cu6n cam 11

B§i 28. Mach c6 R, L, C mac ndi tidp. Cpng hudng dian 21

Sa/ 29. C6ng suat cQa ddng dien xoay chieu. He sd cong sua't 31

6a/ 30. May phat dien xoay chidu 36

Bai 31. D6ng co khdng ddng bp ba pha 45

Bai 32. May bidn ap. Truyen tai dien 54

6a/ 33. Bai tap ve ddng dian xoay chieu 63

6^/ 34. Thuc h^nh: Khao sat doan mach xoay chieu c6 R, L, C mac ndi tiep 72

CHUONG VI. SONG ANH SANG 76

Bdi 35. Tan sac anh sang 76

Bai 36. Nhieu xa anh sang. Giao thoa anh sang 82

Bdi 37. Khoang van. Budc sdng va mau sac anh sang 88

Bdi 38. Bai tap vd giao thoa anh sang 95

Bai 39. May quang phd - Cac loai quang phd 101

Bai 40. Tia hdng ngoai - Tia tfl ngoai 111

Bdi 41. Tia X. Thuydt dien tfl anh sang. Thang sdng didn tfl 120

Bdi 42. Thuc hanh : Xac djnh budc song anh sang i26

261

CHUONG VH. LUONG TCT ANH SANG ^30

6a/ 43. Hien tUpng quang dien ngoai. Cac djnh luat quang dien "^30

Bdi 44. Thuydt lupng tfl anh sang. LUQng tinh song - hat cfla anh sang ' '^8

Bdi 45. Bai tap ve hien tUpng quang dien " 45

Bdi 46. Hien tupng quang dipn trong. Quang dien trd va pin quang dien 151

Bdi 47. Mau nguyen tf l Bo va quang phd vach ci!la nguydn tfl hidrd 159

Bdi 48. Ha'p thu va phan xa Ipc lya anh sang. Mau sac cac vat 165

Bdi 49. s y phat quang. So lUpc ve laze ' '^^

CHUONG Vlll. SO Ll/OC VE THUYllT Tl/ONG 001 HEP 176

6a/ 50. Thuyet tUOng ddi hep "'^^

Bai 51. He thflc Anh - xtanh gifla khdi luong va nSng lupng •'82

CHUONG IX. HAT NHAN NGUYEN Tl!f "" Q

Bai 52. Cau tao hat nhan nguyen tf l - 66 hut khdi ''^S

6a/53. Ph6ng xa ^®®

Bdi 54. Phan flng hat nhan 205

Bai 55. Bai tap ve ph6ng xa va phan flng hat nhan 213

Bdi 56. Phan flng phan hach 220

Bai 57. Phan flng nhiet hach 227

CHUONG X. Tif VI MO OEN V l MO 231

Bai 58. Cac hat so ca'p 231

Bdi 59. Mat Trdi. He Mat Trdi

Bdi 60. Sao. Thian ha

MUG luc

240

248

6a/ 61. Thuyet Big Bang 255

261

262

Thiet k^'bai g iang

VAT LI 12 - NANG CAO - TAP HAI

TRAN THUY HANG - HA DUYEN TUNG

NHA XUAT BAN HANOI

Chiu track nhiem xudt bdn :

NGUYfiN K H A C O A N H

Bien tap:

PHAM QU6C T U A N

Vebia :

TAO THANH H U Y S N

Trinh bay:

CHU MINH

Sda bdn in :

PHAM QU6C T U X N

263

In 1000 cu6'n, kh6 17 x 24 cm, tai Cong ty Co ph^n in Khoa hoc cong

nghe mdi. Gia'y phep xua't ban sd: 68 - 2009/CXB/67 b TK - 06/HN.

In xong va n6p luu chieu nam 2009.

Sach lien ket vdi

Cong ty CO phin In va Phat hanh sach Vi?t Nam

^ • INPHAVI Phat hanh tai Cong ty co phin In va Phat hanh sach Viet Nam

Dia chi: 1 78 - Dong Cac - Dong Da - Ha Noi ' '""=' "" ""^..^J^J ^'^^ O T : ( 0 4 ) 3 5 1 1 5 9 2 1 - F a x : ( 0 4 ) 3 5 1 1 5 9 2 1 ^-^ | | | l l | l l l l | '•'-'

j 34.000 0

Gid: 34.000d

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THIET KE BAI GIANG - f.libvui.comf.libvui.com/dlsm12/ThietKeBaiGiangVatLi12NangCao_a858975d6e.pdf · - Sua't die d6nng tao bdi may phat dien xoay chieu cung co bidu thiic dang nhu