CLASS 12 PHY 1 - 2

7/23/2019 CLASS 12 PHY 1 - 2

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CBSC 2009Physics (Theory) xii (sc)

DESIGN OF QUESTION PAPERTime allowed: 3.00 hours Max. Marks: 0

The !ei"h#a"e o$ #he dis#ri%u#io& o$ marks o'er di$$ere&# dime&sio&s o$ #heues#io& aer shall %e as $ollows:

A. Weightage of content/ subect units

S.&o Co&#e&# * su%+ec# u&i# Marks

, -lec#ros#a#ics 0

2 Curre&# elec#rici#y 0

3 Ma"&e#ic e$$ec# o$ curre&# a&d ma"&e#ism 0

/ -lec#roma"&e#ic i&duc#io& al#er&a#i&" curre&# 0

1 -lec#roma"&e#ic wa'es 03

#ics ,/ 4ual &a#ure o$ ma##er 0/

5#om &ucler 0

9 -lec#ro&ic de'ices 0

,0 Commu&ica#io& sys#em 01

To#al 0

!. Weightage to fo"#s of $uestions%

S.&o 6orm o$ ues#io&s Marks $or eachues#io&

7o. o$ ues#io&s

To#al marks

, 8o&" a&swer #ye 1 3 ,12 Shor# a&swer (i) 3 9 2

3 Shor# a&swer (ii) 2 ,0 20

/ ery shor# a&swer , 0

To#al 30 0

7/23/2019 CLASS 12 PHY 1 - 2


&. Sche#e of o'tions%

,. There will %e &o o'erall o#io&

2. &#er&al choices (ei#her * or #ye) o& a 'ery selec#i'e %asis has %ee& "i'e&

i& $i'e ues#io&s. This i&#er&al choice is "i'e& i& a&y o&e ues#io& o$ 2 marks;a&y , ues#io& o$ 3 marks all #hree ues#io&s o$ 1 marks !ei"h#a"e.

D. A Weightage of about () #a"*s in tota+ has been assigne, to nu#e"ica+.

E. Weightage to ,ifficu+t- +ee+ of $uestion

S.&o -s#ima#ed di$$icul#y le'el o$ ues#io&s Perce&#a"e o$ marks

, -asy ,1

2 5'era"e 0

3 di$$icul# ,1

∗ a. !ei"h#a"e o$ 20< has %ee& assi"&ed #o ues#io& which #es# hi"her

order #hi&ki&" skills (=4TS) o$ s#ude&#s.

7/23/2019 CLASS 12 PHY 1 - 2


!UE PRINT 0I

S.7 >7TS S5(, M5?@S)

S5 (2 M5?@S)

S5 (3 M5?@S)

5(1 M5?@S)

TT58

, -lec#ros#a#ics ,(,) /(2) 3(,) A (/)

2 Curre&# elec#rici#y A 2(,) A 1(,) (2)3 Ma"&e#ic e$$ec# o$curre&# a&dma"&e#ism

,(,) 2(,) A 1(,) (3)

/ -lec#roma"&e#ici&duc#io& al#er&a#i&" curre&#

,(,) /(2) 3(,) A (/)

1 -lec#roma"&e#icwa'es

,(,) 2(,) A A 3(2)

#ics ,(,) 2(,) (2) 1(,) ,/(1)

4ual &a#ure o$ma##er

,(,) A 3(,) A /(2)

5#om &ucler ,(,) 2(,) 3(,) A (3)

9 -lec#ro&ic de'ices ,(,) A (2) A (3),0 Commu&ica#io&sys#em

A 2(,) 3(,) A 1(2)

To#al () 20(,0) 2(9) ,1(3) 0(30)

7/23/2019 CLASS 12 PHY 1 - 2


SA1PE PAPER I

Physics (Theory) ii (Sc)4-S7 6 D>-ST7 P5P-?

Time 5llowed: 3.00 =ours Max. Marks: 0Gene"a+ inst"uctions%

a) 5ll ues#io&s are comulsory.

%) There are 30 ues#io&s i& #o#al. Dues#io& , #o Carry o&e mark each;

ues#io& 9 #o , carry #wo marks each; ues#io& ,9 #o 2 carry #hree marks each

ues#io& 2 #o 30 carry $i'e marks each.

c) There is &o o'erall choice. =owe'er; a& i&#er&al choice has %ee& ro'ided

i& o&e ues#io& o$ #wo marks; o&e ues#io& o$ #hree marks * all #hree ues#io&s

o$ $i'e marks each. Eou ha'e #o a##em# o&ly o&e o$ #he "i'e& choices i& each

ues#io&.

d) >se o$ calcula#or is &o# ermi##ed.

e) Eou may use #he $ollowi&" hysical co&s#a&#s where'er &ecessary:

cF 3x,0 msA,

hF.x,0A3/ GS

eF ,.x,0A,9 C

µ0F /πx ,0A Tm aA,

BolHma&& co&s#a&# @ F ,.3 x ,023 GkA,

5'a"adroIs &o. 7a F .023x,023* Mole

Mass o$ &eu#ro& Ma& F ,.x,0A2 k"

Mass o$ elec#ro& me F 9.0,x,0A3, k"

,. Je&er diodes ha'e hi"her doa&# de&si#ies as comared #o ordi&ary A&

+u&c#io& diode. =ow does i# a$$ec# (i) wid#h o$ dele#io& layerK (%) Gu&c#io& $ieldK

2. 5 ar#ially la&e olarised %eam o$ li"h# is assed #hrou"h a olaride.

Show "rahically #he 'aria#io& o$ #he #ra&smi##ed li"h# i&#e&si#y wi#h a&"le o$

ro#a#io& o$ #he Polaroid.

3. !ha# is #he a&"le %e#wee& #he direc#io&s o$ elec#ric $ield a# a&y (i) axial

oi&# a&d (ii) eui#orial oi&# due #o a& elec#ric dioleK

7/23/2019 CLASS 12 PHY 1 - 2


/. 6our &ucler o$ a& eleme&# $use #o"e#her #o $orm a hea'ier &ucleus. $ #he

rocess is accoma&ied %y release o$ e&er"y; which o$ #he #wo #he are&# or #he

dau"h#er &ucleus would ha'e a hi"her %e&di&" e&er"y*&ucleo&K

1. The deA%ro"lie wa'ele&"#h; associa#ed wi#h a ro#o& a &eu#ro&; are

$ou&d #o %e eual. !hich o$ #he #wo has hi"her 'alue $or ki&e#ic e&er"yK

. i'e exressio& $or #he a'era"e 'alue o$ #he a.c. 'ol#a"e 'F'0 si& ω# o'er

#he #ime i&#er'al #F0 #F π*ω

. S#a#e #he co&di#io& u&der which a microwa'e o'e& hea#s u a $ood i#em

co&#ai&i&" wa#er molecules e$$icie&#ly.

. 5 (hyo#he#ical) %ar ma"&e# (5B) is cu# i&#o #wo eual

ar#s. &e ar# is &ow ke# o'er #he o#her; so #a# ole c2 is

a%o'e c,. $ M is #he ma"&e#ic mome&# o$ #he ori"i&al ma"&e#;

which would %e #he ma"&e#ic mome&# o$ #he com%i&a#io& so

$ormed.

9. The #wo "rahs draw& %elow; show #he 'aria#io& o$

elec#ros#a#ic o#e&#ial () wi#h *r (r %ei&" dis#a&ce o$ #he $ield oi&#

$rom #he oi&# char"e) $or #wo oi&# char"es D, D2

(i) !ha# are #he si"&s o$ #he #wo char"esK

(ii) !hich o$ #he #wo char"es has a lar"er ma"&i#ude whyK

,0. 5 oi&# char"e L ,0µC is a# a dis#a&ce 1 cm direc#ly a%o'e

#he ce&#re o$ suare o$ side ,0 cm as show& i& $i". wha# is #he

ma"&i#ude o$ #he elec#ric $lux #hrou"h #he suareK

,,. 5 char"ed ar#icle mo'i&" wi#h a u&i$orm 'eloci#y ' e&#ers a re"io& where

u&i$orm elec#ric ma"&e#ic $ield - B are rese&#. # asses #hrou"h #he re"io&

wi#hou# a&y cha&"e i& i#s 'eloci#y. !ha# ca& we co&clude a%ou#

(i) ?ela#i'e direc#io&s o$ -; BK

(ii) Ma"&i#ude o$ -; BK

7/23/2019 CLASS 12 PHY 1 - 2


,2 -xerime&#al o%ser'a#io&s ha'e show& #ha# Arays

(i) Tra'el i& 'acuum wi#h a seed o$ 3x,0 msA,.

(ii) -xhi%i#s #he he&ome&o& o$ di$$rac#io&s olariHa#io&.

!ha# co&clusio& ca& %e draw& a%ou# #he &a#ure o$ xArays; $rom each o$ #hese

o%ser'a#io&sK

,3 5 radioac#i'e ma#erial is reduced #o ,*, o$ i#s ori"i&al amou&# i& /

days. =ow much ma#erial should o&e %e"i& wi#h so #ha# /x,0A3 @ o$ ma#erial is

le$# a$#er daysK

,/ 4is#i&"uish %e#wee& oi&# #o oi&#I %roadcas#I commu&ica#io&

modes. i'e o&e examle o$ each.

,1 6i". Shows a li"h# %ul% (B) iro&Acored i&duc#or co&&ec#ed #o a 4C

%a##ery #hrou"h a swi#ch (S).

(i) !ha# will o&e o%ser'e whe& swi#ch(s) is

closedK

(ii) =ow wills #he "low o$ #he %ul% cha&"e whe& #he %a##ery is

relaced %y a& ac source o$ rms 'ol#a"e eual #o #he 'ol#a"e o$ dc %a##eryK

r

5& air cored coil l a %ul% are co&&ec#ed i& series #o

#he ac mai&s as show& i& "i'e& $i"ure:

The %ul% "lows o$ #he %ul% cha&"e i$ a& iro& rod were

i&ser#ed i& #he coilK i'e reaso&s i& suor# o$ your a&swer.

,. Two ide&#ical la&e me#allic sur$aces 5B are ke# arallel #o each o#her i&

air seara#ed %y a dis#a&ce o$ ,0 cm as show&

i& #he $i"ure sur$ace 5 is "i'e& a osi#i'e

o#e&#ial o$ ,0' #he o#her sur$ace o$ % is

ear#hed.

(i) !ha# is #he ma"&i#ude direc#io& o$ #he u&i$orm elec#ric $ield %e#wee&

oi&#s E JK

(ii) !ha# is #he work do&e i& mo'i&" a cha&"e o$ 20µc $rom oi&# #o EK

,. 6i"ure show& #o lo&" coaxial sole&oids;

each o$ le&"#h N8I. The ou#er sole&oid has a&

7/23/2019 CLASS 12 PHY 1 - 2


area o$ crossAsec#io& 5; a&d &um%er o$ #ur&s* le&"#h & ,. The correso&di&"

'alues $or #he i&&er sole&oid are 52 &2. !ri#e #he exressio& $or sel$ i&duc#a&ce

8,; 82 o$ #he coils #heir mu#ual i&duc#a&ce M. he&ce show #ha# M O √8,82.

,. !hy we ca& &o# use "rou&d wa'e roa"a#io& a&d sky wa'e roa"a#io& $or

commu&ica#io& o$ T.. si"&alsK

,9. 5& elec#ric diole o$ diole mome&# is laced i& a u&i$orm elec#ric $ield -.

!ri#e #he exressio& $or #he #orue # exerie&ced %y #he diole. de&#i$y #wo airs

o$ ere&dicular 'ec#ors i& #he exressio&. Show dia"ramma#ically #he orie&#a#io&

o$ #he diole i& #he $ield $or which #he #orue is (i) maximum; (ii) hal$ #he maximum

'alue (iii) Hero.

r

Two caaci#ors wi#h caaci#y C, C2 are char"ed #o o#e&#ial , 2

resec#i'ely #he& co&&ec#ed i& arallel. Calcula#e #he commo& o#e&#ial across

#he com%i&a#io&; #he char"e o& each caaci#or; #he elec#ros#a#ic e&er"y s#ored i&

#he sys#em #he cha&"e i& #he elec#ros#a#ic e&er"y $rom i# i&i#ial 'alue.

20. Show #ha# duri&" #he char"i&" o$ a arallel la#e caaci#or; #he ra#e o$ cha&"e

o$ char"e o& each la#e euals E2 #imes #he ra#e o$ cha&"e o$ elec#ric $lux φe

li&ked wi#h i#. !ha# is #he &ame "i'e& #o #he #erm E2(d φe*d#)K

2,. !hich #wo mai& co&sidera#io&s are ke# i& mi&d while desi"&i&" #he

No%+ec#i'eI o$ a& as#ro&omical #elescoeK %#ai& a& exressio& $or #he a&"ular

ma"&i$yi&" ower #he le&"#h o$ #he #u%e o$ a& as#ro&omical #elescoe i& i#s

N&ormal ad+us#me&#I osi#io&.

22. !ha# is sace wa'e roa"a#io&K !hich #wo commu&ica#io& me#hods make

use o$ #hus mode o$ roa"a#io&K $ #he sum o$ #he hei"h# o$ #ra&smi##i&"

recei'i&" a&#e&&a i& li&e o$ ri"h# o$ commu&ica#io& is $ixed a# h; show #he ra&"e is

maximum whe& #he #wo a&#e&&as ha'e a hei"h# h*2 each.23. 4raw #he #ra&s$er charac#eris#ics o$ a %ase %iased #ra&sis#or i& i#s commo&

emi##er co&$i"ura#io&. -xlai& %rie$ly #he mea&i&" o$ #he #erm Nac#i'e re"io&I i&

#hese charac#eris#ics. 6or wha# rac#ical use; do we use #he #ra&sis#or i& #his

Nac#i'e re"io&IK

7/23/2019 CLASS 12 PHY 1 - 2


2/. !ha# is a wa'e$ro&#K 4is#i&"uish %e#wee& a la&e wa'e$ro&# a sherical

wa'e$ro&#.

-xlai& wi#h #he hel o$ dia"ram; #he re$rac#io& o$ a la&e wa'e$ro&# a# a la&e

sur$ace usi&" =uy"e&sIs co&s#ruc#io&.

21. 4e$i&e #he #erm ac#i'i#yI o$ a radioac#i'e su%s#a&ce. S#a#e i#s S u&i#. Two

di$$ere&# radioac#i'e eleme&#s wi#h hal$Ali'es #, #2 ha'e &, &2 (u&decayed)

a#oms resec#i'ely rese&# a# a "i'e& i&s#a&#. 4e#ermi&e #he ra#io o$ #heir ac#i'i#y

a# #his i&s#a&#.

2. Calcula#e #he deA%ro"lie wa'ele&"#h o$ (i) a& elec#ro& (i& #he hydro"e& a#om)

mo'i&" wi#h a seed o$ ,*,00 o$ #he seed o$ #he li"h# i& 'acuum (ii) a %all o$

radius 1 mm mass 3x,0A2k" mo'i&" wi#h a seed o$ ,00 msA,. =e&ce; show #ha#

#he wa'e &a#ure o$ ma##er is imor#a&# a# #he a#omic le'el %u# is &o# really rele'a&#

a# #he macroscoic le'el.

2. >si&" a sui#a%le com%i&a#io& $rom a 7? a& ? a 7T "a#e; draw circui#s

#o o%#ai& #he #ru#h #a%le "i'e& %elow.

(i) 5 B E (ii) 5 B E

0 0 0 0 0 ,

0 , 0 0 , ,

, 0 , , 0 0

, , 0 , , ,

2. (a) draw #he la%eled dia"ram o$ mo'i&" coil "al'a&ome#er. Pro'e #ha# i& a

radial ma"&e#ic $ield; #he de$lec#io& o$ #he coil is direc#ly roor#io&al #o #he

curre&# $lowi&" i& #he coil.

(%) 5 "al'a&ome#er ca& %e co&'er#ed i&#o a 'ol#me#er #o measure u#o

(i) NI 'ol#s %y co&&ec#i&" a resis#a&ce ?, i& series wi#h coil

(ii) *2 'ol#s %y co&&ec#i&" a resis#a&ce ?2 i& series wi#h i#s coil

6i&d #he resis#a&ce (?); i& #erms o$ ?, ?2 reuired #o co&'er# i# i&#o a 'ol#me#er

#ha# ca& read u#o N2I 'ol#.

29. 5 cell o$ u&k&ow& em$ - i&#er&al resis#a&ce r; #wo u&k&ow& resis#a&ce ? ,

?2

(?, ?2) a er$ec# amme#er are "i'e&. The curre&# i& #he circui# is measured i&

$i'e di$$ere&# si#ua#io&s:

7/23/2019 CLASS 12 PHY 1 - 2


(i) wi#hou# a&y ex#er&al resis#a&ce i& #he circui#; (ii) wi#h resis#a&ce ?, o&ly

(iii) !i#h resis#a&ce ?2 o&ly; (i') wi#h %o#h ?, ?2 used i& series com%i&a#io&

(') wi#h ?, ?2 used i& arallel com%i&a#io&.

The curre&# o%#ai&ed i& #ha# order. de&#i$y #he curre&# i& #he $i'e cases lis#ed

a%o'e calcula#e -; r; ?, ?2.

or

4escri%e #he $ormula $or #he eui'ale&# em$ i&#er&al resis#a&ce $or #he arallel

com%i&a#io& o$ #wo cells wi#h -, -2 i&#er&al resis#a&ce r , r 2 resec#i'ely.

!ha# is #he correso&di&" $ormula $or #he series com%i&a#io&K Two cells o$ em$

,; 2 i&#er&al resis#a&ce 2Ω ,Ω resec#i'ely are co&&ec#ed i& (i) series; (ii)

i& arallel. !ha# should %e #he ex#er&al resis#a&ce i& #he circui#; so #ha# #he

curre&# #hrou"h #he resis#a&ce %e #he same i& #he casesK & which case more

hea# is "e&era#ed i& #he cellsK

30. (i) deri'e #he mirror $ormula which "i'es #he rela#io& %e#wee& ƒ; ' u. wha# is

#he correso&di&" $ormula $or a #hi& le&sK

(ii) Calcula#e #he dis#a&ce d; so #ha# a real

ima"e o$ a& o%+ec# a# o; ,1cm i& $ro&# o$ a

co&'ex le&s o$ $ocal le&"#h ,0cm is $ormed a#

#he same oi&# o. #he radius o$ cur'a#ure o$ #hemirror is 20 cm. will #he ima"e is i&'er#ed or

erec#K

r

(i) >si&" #he rela#io& $or re$rac#io& a# a si&"le sherical re$rac#i&" sur$ace;

de'ice #he le&s makerIs $ormula $or a #hi& co&'ex le&s.

(ii) & #he accoma&yi&" dia"ram; #he

direc# ima"e $ormed %y #he le&s (ƒ F ,0cm) o$ a&

o%+ec# laced a# 0I #ha# $ormed a$#er re$lec#io&

$rom #he sherical mirror are $ormed a# #he same

oi&# 0. !ha# is #he radius o$ cur'a#ure o$ #he

mirrorK

7/23/2019 CLASS 12 PHY 1 - 2


!UE PRINT 0II

S.7 >7TS S5(, M5?@S)

S5 (2 M5?@S)

S5 (3 M5?@S)

5(1 M5?@S)

TT58

, -lec#ros#a#ics A 2(,) (2) A (3)

2 Curre&# elec#rici#y A /(2) 3(,) A (3)

3 Ma"&e#ic e$$ec# o$curre&# a&dma"&e#ism

,(,) 2(,) A 1(,) (3)

/ -lec#roma"&e#ici&duc#io& al#er&a#i&" curre&#

2(2) Q (2) A (/)

1 -lec#roma"&e#icwa'es

,(,) 2(,) A A 3(2)

#ics ,(,) 2(,) (2) 1(,) ,/(1)

4ual &a#ure o$ma##er

Q /(2) 3(,) A /(2)

5#om &ucler ,(,) 2(,) A A (3)

9 -lec#ro&ic de'ices 2(2) A 3(,) 1(,) (3)

,0 Commu&ica#io&sys#em

A 2(,) A A 1(2)

To#al () 20(,0) 2(9) ,1(3) 0(30)

7/23/2019 CLASS 12 PHY 1 - 2


SA1PE PAPER II

Physics (Theory) ii (Sc)

4-S7 6 D>-ST7 P5P-?

Time 5llowed: 3.00 =ours Max. Marks: 0

Gene"a+ inst"uctions%

a. 5ll ues#io&s are comulsory.

%. There are 30 ues#io&s i& #o#al. Dues#io& , #o Carry o&e mark each;

ues#io& 9 #o , carry #wo marks each; ues#io& ,9 #o 2 carry #hree

marks each ues#io& 2 #o 30 carry $i'e marks each.

c. There is &o o'erall choice. =owe'er; a& i&#er&al choice has %ee& ro'ided

i& o&e ues#io& o$ #wo marks; o&e ues#io& o$ #hree marks * all #hree

ues#io&s o$ $i'e marks each. Eou ha'e #o a##em# o&ly o&e o$ #he "i'e&

choices i& each ues#io&.

d. >se o$ calcula#or is &o# ermi##ed.

e. Eou may use #he $ollowi&" hysical co&s#a&#s where'er &ecessary:

cF 3x,0 msA,

hF.x,0A3/ GS

eF ,.x,0A,9 C

µ0F /πx ,0A Tm aA,

BolHma&& co&s#a&# @ F ,.3 x ,023 GkA,

5'o"adroIs &o. 7a F .023x,023* Mole

Mass o$ &eu#ro& M& F ,.x,0A2 k"

Mass o$ elec#ro& me F 9.0,x,0A3, k"

,. 5& αA ar#icle a ro#o& are mo'i&" i& #he la&e o$ #he aer i& a re"io&

where #here is a u&i$orm ma"&e#ic $ield (B) direc#ed &ormal #o #he la& o$ #he

aer. $ #he ar#icles ha'e eual li&ear mome&#a; wha# will %e #he ra#io o$ #he

ra#io o$ #heir #ra+ec#ory i& #he $ieldK

2. 5& elec#rical eleme&# ; whe& co&&ec#ed #o a& al#er&a#i&" 'ol#a"e source;

has #he curre&# #hrou"h i# leadi&" #he 'ol#a"e %y π*2 radia&. de&#i$y wri#e a&

exressio& $or i#s reac#a&ce.

7/23/2019 CLASS 12 PHY 1 - 2


3. !hy a me#allic iece does %ecome 'ery ho# whe& i# is surrou&ded %y a

coil carryi&" hi"h $reue&cy al#er&a#i&" curre&#K

/. 7ame #he charac#eris#ic o$ elec#roma"&e#ic wa'e #ha#:

(i) i&creases (ii) remai&s co&s#a&#

& elec#roma"&e#ic sec#rum as o&e mo'e $rom radio wa'e re"io& #owards

ul#ra'iole# re"io&.

1 =ow #he a&"ular seara#io& o$ i&#er$ere&ce $ri&"es i& you&"Is dou%le sli#

exerime&# cha&"e whe& #he dis#a&ce o$ seara#io& %e#wee& #he scree& #he sli#

is dou%ledK

. Calcula#or #he ra#io o$ e&er"ies o$ ho#o&s roduced due #o #ra&si#io& o$

elec#ro& o$ hydro"e& a#om $rom i#s;

(i) Seco&d ermi##ed e&er"y le'el #o #he $irs# le'el

(ii) =i"hes# ermi##ed e&er"y le'el #o #he seco&d ermi##ed le'el

. Car%o& silico& are k&ow& #o ha'e similar la##ice s#ruc#ures .howe'erR #he $our

%o&di&" elec#ro&s o$ car%o& are rese&# i& seco&d or%i# while #hose o$ silico& are

rese&# i& #hird or%i#. =ow does #his di$$ere&ce resul# i& a di$$ere&ce i& #heir

elec#rical co&duc#i'i#iesK

. =ow is #he %a&d "a; -"; o$ a ho#o diode rela#ed #o maximum wa'ele&"#h; λ

#ha# ca& %e de#ec#ed %y i#K9. The A' charac#eris#ic o$ a resis#or is o%ser'ed #o de'ia#e $rom a s#rai"h# li&e

$or hi"her 'alues o$ curre&# as show& %elow. !hyK

,0. -xlai& how #he a'era"e 'eloci#y o$ $ree elec#ro&s i& a me#al a# co&s#a&#

#emera#ure; i& a& elec#ric $ield; remai&s co&s#a&# e'er #hou"h #he elec#ro&s are

%ei&" co&s#a&#ly accelera#ed %y #his elec#ric $ield

7/23/2019 CLASS 12 PHY 1 - 2


,,. !ha# is #he %asic di$$ere&ce %e#wee& #he a#om or molecule o$ a diama"&e#ic

a arama"&e#ic ma#erialK !hy are eleme&#s wi#h e'e& a#omic &um%er more

likely #o %e diama"&e#icK

,2. -lec#roma"&e#ic radia#io& wi#h wa'ele&"#h

(i) λ, is used #o kill "erms o& wa#er uri$iers.

(ii) λ2 are used i& T commu&ica#io& sys#em

(iii) λ3 lay a& imor#a&# role i& mai&#ai&i&" #he ear#hIs warm#h

7ame #he ar#s o$ elec#roma"&e#ic sec#rum #o which #hese radia#io&s %elo&".

5rra&"e #hese wa'ele&"#hs i& decreasi&" order o$ #heir ma"&i#ude.

,3.8i"h# o$ wa'ele&"#h 110 &m is i&cide&# as arallel %eam o& a sli# o$ wid#h 0.,

mm. $i&d #he a&"ular wid#h li&ear wid#h o$ #he ri&cial maxima i& #he resul#i&"

di$$rac#io& a##er& o& a scree& ke# a# a dis#a&ce o$ ,., m $rom #he sli#. !hich o$

#his wid#h would &o# cha&"e i$ #he scree& were mo'ed #o a dis#a&ce o$ 2.2 m $rom

#he sli#K

,/.Pro'e #ha# #he i&s#a&#a&eous ra#e o$ cha&"e o$ #he ac#i'i#y o$ a radioac#i'e

su%s#a&ce is i&'ersely roor#io&al #o #he suare o$ i#s hal$ li$e.

,1.Two s#ude&#s E er$orm a& exerime&# o& o#e&#iome#er seara#ely usi&"

circui# dia"ram show& here

@eei&" o#her #hi&" u&cha&"ed

(,) i&creases #he 'alue o$ resis#a&ce r

(2) E decreases #he 'alue o$ resis#a&ce S i& #he se# u.

=ow would #hese cha&"es a$$ec# #he osi#io& o$ &ull oi&# i& each case whyK

7/23/2019 CLASS 12 PHY 1 - 2


,. The $ollowi&" #a%le "i'es #he 'alue o$ work $u&c#io& $or a $ew ho#o se&si#i'e

me#als

S.&o Me#al !ork

$u&c#io&(e'

),. 7a ,.92

2. @ 2.,1

3. Mo /.,

$ each o$ #hese me#als is exosed #o radia#io&s o$

wa'ele&"#h300&m; which o$ #hem will &o# emi# ho#oelec#ro&s whyK

?

By how much would #he s#oi&" o#e&#ial $or a "i'e& ho#ose&si#i'e sur$ace "o

u i$ #he $reue&cy o$ #he i&cide&# radia#io&s were #o %e

&creased $rom /x,0,1 =H #o x ,0,1 =H .

(i'e&: h F./,0A3/ is; eF,.,0A,9C CF3,0 m1,)

$ each o$ #hese me#als is exosed #o radia#io&s o$ wa'ele&"#h 300 &m; which o$

#hem will &o# emi# ho#oelec#ro&s whyK

,. !ha# does #he #erm 8S commu&ica#io& mea&K 7ame #he #ye o$ wa'es

#ha# are used $or #his commu&ica#io&. !hich o$ #he #woAhei"h# o$ #ra&smi##i&"

a&#e&&a hei"h# o$ recei'i&" a&#e&&a ca& a$$ec# #he ra&"e o'er which #his modeo$ commu&ica#io& remai&s e$$ec#i'eK

,. !ha# is ho#oelec#ric e$$ec#K Calcula#e #he #hreshhold $reue&cy o$ ho#o& $or

ho#oelec#ric emissio& $rom a me#al o$ work $u&c#io& 0., e'.

,9. !ha# is a wa'e$ro&#K 4is#i&"uish %e#wee& a la&e wa'e$ro&# a sherical

wa'e$ro&#. -xlai& wi#h #he hel o$ 4ia"ram #he re$rac#io& o$ a la&e wa'e$ro&# a#

a la&e sur$ace usi&" =uy"e&sIs co&s#ruc#io&.

20. ,2 cells; each o$ em$ ,.1 ' i&#er&al re$rac#io& 2.) Ω are arra&"ed i& mI rows

each co&#ai&i&" &I cells co&&ec#ed i& series; as show&

Calcula#e #he 'alues o$ & m $or which #his

com%i&a#io& would se&d maximum curre&#

#hrou"h a& ex#er&al resis#a&ce o$ ,.)Ω

.

7/23/2019 CLASS 12 PHY 1 - 2


6or #he circui# show& here; calcula#e #he

o#e&#ial di$$ere&ce %e#wee& oi&# B

4.

2,. 5 char"e D loca#ed a# a oi&# r is i& euili%rium u&der #he com%i&ed elec#ric

$ield o$ #hree char"es ,; 2; 3. $ #he char"es ,; 2; are loca#ed a# oi&# r , r 2

resec#i'ely; $i&d #he direc#io& o$ #he $orce o& D; due #o 3 i& #erms o$ ,; 2; 2;

r ,; r 2; r.

22. The #wo "rahs draw& %elow; show #he 'aria#io& o$ elec#ros#a#ic o#e&#ial ()

wi#h ,*r (r %ei&" dis#a&ce o$ #he $ield oi&# $rom #he oi&#

char"e) $or #wo oi&# char"es , 2.

(i) !ha# are #he si"&s o$ #he #wo char"esK

(ii) !hich o$ #he #wo char"es has a lar"er ma"&i#ude

whyK

23. 5 circular coil ha'i&" 20 #ur&s; each o$ radius cm; is ro#a#i&" a%ou# i#s

'er#ical diame#er wi#h a& a&"ular seed o$ 10 radia& sA, i& a u&i$orm horiHo&#al

ma"&e#ic $ield o$ ma"&i#ude 30 mT. %#ai& #he maximum a'era"e r.m.s 'alue

o$ #he em$ i&duced i& #he coil.

$ #he coil $orms a closed loo o$ resis#a&ce ,0 U; how much ower is

dissia#ed as hea# i& i#K

2/. 4e$i&e #he #erm modula#io& i&dexI $or a& 5M wa'e. !ha# would %e

modula#io& i&dex $or a& 5M wa'e $or which #he maximum amli#ude is aI; !hile

#he mi&imum amli#ude is %IK

21.The &ucleus o$ a& a#om o$ ; 3445)- i&i#ially a# res#; decays %y emi##i&" a& αA

ar#icle as er #he eua#io&

3445)- 32

45(6 7 489e 7 ene"g-

7/23/2019 CLASS 12 PHY 1 - 2


# is "i'e& #ha# #he %i&di&" e&er"ies er &ucleo& o$ #he are&# dau"h#er

&uclear are .Me' .31Me' resec#i'ely a&d #ha# o$ αAar#icle is .0 Me' *

&ucleo&. 5ssumi&" #he dau"h#er &ucleus #o %e $ormed i& #he u&exci#ed s#a#e

&e"lec#i&" i#s share i& #he e&er"y o$ #he reac#io&; calcula#e #he seed o$ emi##ed

αAar#icle. Take mass o$ α ar#icle #o %e .x,0A2 k".

2. whe& a circui# eleme&#s is co&&ec#ed across a& a.c. source ;a curre&# o$

√2 5 $lows #hrou"h i# #his curre&# is i& hase wi#h #he alied 'ol#a"e. whe&

a&o#her eleme&# yI is co&&ec#ed across #he same a.c. source ;#he same curre&#

$lows i& #he circui# %u# i# leads #he 'ol#a"e %y π*2 radia&s .

(i) 7ame #he circui# eleme&#s E .

(ii) 6i&d #he curre&# #ha# $lows i& #he circui# whe& #he series com%i&a#io& o$ E

is co&&ec#ed across #he same a.c. 'ol#a"e.

(iii) Bol# a "rah showi&" 'aria#io& o$ #he &e# imeda&ce o$ #his series

com%i&a#io& o$ E as a $u&c#io& o$ a&"ler $reue&cy IωI o$ #he alied 'ol#a"e.

2. i'e reaso&s $or #he $ollowi&":

(a) 5s#ro&omical re$er #o use #elescoes wi#h lar"e o%+ec#i'e diame#er #o

o%ser'e as#ro&omical o%+ec#s.

(%) Two ide&#ical %a# i&dee&de&# mo&ochroma#ic sources o$ li"h# ca&I# %e

cohere&#.

(c) The 'alue o$ Brews#er a&"le $or a #ra&sare&# medium is di$$ere&# $or li"h#s o$

di$$ere&# color

7/23/2019 CLASS 12 PHY 1 - 2


2. 5 s#ude&# has #o s#udy #he i&u# ou#u# charac#eris#ic o$ &AA& silico&

#ra&sis#or i& commo& emi##er co&$i"ura#io&. !ha# ki&d o$ a circui# arra&"eme&#

should she use $or #his uroseK 4raw #he #yical shae o$ i&u# charac#eris#ic

likely #o %e o%#ai&ed %y her. !ha# do we u&ders#a&d %y #he cu# o$$; ac#i'e

sa#ura#io& s#a#es o$ #he #ra&sis#orK & which o$ #hese o$ s#a#es does #he #ra&sis#or

&o# remai& whe& %ei&" used as a swi#chK

r

&u# si"&als 5 IBI are alied #o #he i&u# #ermi&al o$ #he do##ed %ox se#A

u show& here. 8e# E %e #he $i&al ou#u# si"&al $rom #he %ox

4raw #he wa'e $orms o$ #he si"&al la%eled as c, c2 wi#h i& #he %ox;

"i'i&" (i& %rie$) #he reaso& $or "e##i&" #his wa'e $orm. =e&ce draw #he wa'e o$ #he

$i&al ou#u# si"&al E. "i'e reaso& $or your choice. !ha# ca& we s#a#e (i& words) as

#he rela#io& %e#wee& #he $i&al ou#u# si"&al E #he i&u# si"&al 5BK

29. Two circular coils E ha'i&" radii ? r*2 resec#i'ely are laced i&

horiHo&#al la&e wi#h #heir ce&#ers coi&cidi&" wi#h each o#her. Coil has a curre&#

$lowi&" #hrou"h i# i& #he clockwise se&se .wha# mus# %e #he curre&# i& coil E #o

make #o#al ma"&e#ic $ield a# #he commo& ce&#er o$ #he #wo coils ;Hero K !i#h #he

same curre&# $lowi&" i& #he #wo coils; i$ #he coil E is &ow li$#ed 'er#ically uwards

#hrou"h a dis#a&ce ?; wha# would %e #he &e# ma"&e#ic $ield a# #he ce&#er o$ coil

EK

r

5 s#rai"h# #hick li&" wire o$ u&i$orm cross sec#io& o$ radius a is carryi&" a

s#eady curre&# . use amereIs circui#al law #o o%#ai& a rela#io& showi&" #he

'aria#io& o$ #he ma"&e#ic $ield (B) i&side ou#side #he wire wi#h dis#a&ce r ;(r ≤ a )

(r a) o$ #he $ield oi&# $rom #he ce&#er o$ i#s cross sec#io& . Plo# a "rah

7/23/2019 CLASS 12 PHY 1 - 2


showi&" #he &a#ure o$ #his 'aria#io&. Calcula#e #he ra#io o$ ma"&e#ic $ield a# a

oi&# a*2 a%o'e #he sur$ace o$ #he wire #o #ha# a# a oi&# a*2 %elow i#s sur$ace.

!ha# is #he maximum 'alue o$ #he $ield o$ #his wireK

30 (a) 4raw a ray dia"ram #o show #he re$rac#io& o$ li"h# #hrou"h a "lass rism.

=e&ce o%#ai& #he rela#io& $or #he a&"le o$ de'ia#io& i& #er&s o$ #he a&"le o$

i&cide&#; a&"le o$ emer"e&ce #he a&"le o$ #he rism.

(%) 5 ri"h# a&"le isosceles rism is made $rom "lass o$ re$rac#i'e i&dex ,.1

.show #ha# a ray o$ li"h# i&cide&# &ormally o&

(i) &e o$ #he eual sides o$ #his rism is deri'a#ed #hrou"h 90o

(ii) The hyo#e&use o$ #his rism is de'ia#ed #hrou"h ,00

r

(a) !i#h #he hel o$ a la%eled ray dia"ram; show #he ima"e $orma#io& %y a

comou&d microscoe. 4eri'e a& exressio& $or i#s ma"&i$yi&" ower.

(%) =ow does #he resoli'&" ower o$ a comou&d microscoe "e# a$$ec#ed

o&K

(ii) 4ecreasi&" #he diame#er o$ i#s o%+ec#i'eK

(ii) &creasi&" #he $ocal le&"#h o$ i#s o%+ec#i'eK

Documents

CLASS 12 PHY 1 - 2