01. Dai Cuong Ve Dong Dien Xoay Chieu (Ban in).2295

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Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang1 CH I. ICNG V DNG INXOAYCHIU A. TM TT KINTHC CNBN 1.Sut inngxoay chiu Chomtkhungdydnphngquayuvitc gcquanhmttrcvunggcviccngsc camtttrnguccmngtB.Theonh lutcmngintthtrong khung dy xut hin mt sutinngbinthintun hon theo thi gian theo quylut: ) cos(0 et E e e + =trong :00 > E l sut in ng cc i el sut in ng tc thi el tns gc ca sutin ng el phabanu (pha thi im t = 0) ) (et e +l pha thi im t Chuk T vtn s f casut in ng e xc nhtheo tn s gc theo cc cng thc : et 2= T te21= =TfSutin ng camyphtin xoaychiu cngc dng) cos(0 et E e e + = . 2.in p xoay chiu.Dng inxoay chiu Nihaicccamyphtinxoaychiuvimtonmchtiuthinthgiahai uonmchcmthiuinthbinthiniuhotheotheothi gian vi tn s bng tnscasutinngdomyphtintoravcgilhiuinthxoaychiu hayin p xoay chiu. Trongtrnghptngqut,biuthcinpgiahaiuonmchinxoaychiu no vcng dng in quan c dnglnlt l : ) cos(0 ut U u e + =v) cos(0 it I i e + =trong : u l in ptc thi U0 l in p cc i (bin ca in p) l tns gc ca in p ul phabanuca in p(phati thi im t = 0) ) (ut e +l phati thi im t cain p vi l cng tc thi ca dngin I0 l cng cc i (bin ) ca dngin l tns gc ca dngin i l phabanu ca dngin (phati thi im t = 0) ) (it e +l phati thi im t cadngin n B eKhi khung dy quay u trong t trng,trongkhungdyxut hin sut in ng xoay chiu Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang2 lch phagiain pu vcng dng in i l : i u =Nu > 0 th u sm pha(nhanhpha)so vi i. Nu < 0 th u tr pha(chmpha)so vi i. Nu = 0 th u ng pha(cngpha)vii. 3.Gi tr hiudng Dnginxoaychiucngctcdngtonhitnhdnginmtchiu.Xtvmt tonhittrongmtthigiandithdng in xoay chiu) cos(0 it I i e + =tng ng vi dngin mt chiu khngi c cng bng20I. Cnghiudngcadnginxoaychiubngcngcamtdngin khngi,nuchohaidnginlnltiquacngmtintrtrongnhng khongthigianbngnhaudith nhit lng to ra bng nhau. N c gi tr bng cng cc i chia cho2 . Dngin xoaychiu) cos(0 it I i e + =c cng hiu dngl : 20II =Tngt,inpxoaychiu) cos(0 ut U u e + = vsutinngxoaychiu ) cos(0 et E e e + =c tr hiu dnglnlt l : 20UU = 20EE =oinphiudngvcnghiudngcadnginxoaychiu ngi ta dng vnk vampek xoaychiu. B. MT S BI TP Bi1:MtkhungdydnphngcdintchS=50cm2,cN=100vngdy,quay uvitc50vng/giyquanhmttrcvung gc vi cc ng sc ca mt t trng uccmngtB=0,1T.Chngcthigiant=0llcvectphptuynncadin tchScakhungdycngchiuvivectcmngtBvchiudnglchiuquayca khungdy. a)Vit biu thc xcnh t thnguquakhungdy. b)Vit biu thc xcnh sut in ng e xuthin trong khungdy. c)V th biu din s bin i ca e theo thi gian. Bi gii : a)Khungdydnquayu vitc gc : = 50.2 = 100rad/s Tithiimbanut=0,vectphptuynncadintchScakhungdyc chiu trngvichiucavectcmngtBcattrng.nthiimt,phptuynnca khungdy quayc mt gc bngt e . Lcnyt thngquakhungdyl : Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang3 ) cos( t NBS e | =Nhvy,tthngquakhungdybinthiniuhotheothigianvitnsgcv vigitr cc i (bin ) l 0 = NBS. ThayN=100,B=0,1T,S= 50 cm2 = 50. 10-4 m2 v = 100 rad/s ta c biu thc ca t thngquakhungdyl : ) 100 cos( 05 , 0 t t | =(Wb) b)Tthngquakhungdybinthiniuhotheothigian,theonhlutcmng in t ca Faradayth trong khungdyxuthin mt sut in ng cm ng. Sutin ng cmngxuthin trong khungdyc xcnh theo nh lutLentz : |.|

\| = = = =2cos ) sin( ') (te e e e ||t NBS t NBSdtdet Nhvy,sutinngcmngxuthintrongkhungdybiniiuhotheothi gianvitns gc vvigitr cc i (bin ) l E0 = NBS. ThayN=100,B=0,1T,S= 50 cm2 = 50. 10-4 m2 v = 100 rad/s ta c biu thc xc nhsut in ng xuthin trong khungdyl : |.|

\| =2100 cos 5tt t t e(V) hay|.|

\| ~2314 cos 7 , 15tt e(V) c)Sutinngxuthintrongkhungdy bin i iu ho theo thi gian vi chu kh T vtn s f lnlt l : 02 , 01002 2= = =ttetTs 5002 , 01 1= = =TfHz thbiudinsbinicasutinngetheothigiantlnghnhsinc chu k tunhonT = 0,02 s. Bnggitrcasutinngetimtsthiimcbitnh:0s,005 , 04 =Ts, 01 , 02 =T s,015 , 043=T s,02 , 0 = T s,025 , 045=T s v03 , 023=T s : t (s)00,0050,010,0150,020,0250,03 e (V)015,70-15,7015,70 th biu dins phthuc cae theo t nhhnhdi: t (s) e (V) 0 + 15,7 - 15,7 0,005 0,015 0,0250,010,02 0,03 Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang4 Bi2:Biuthcinpxoaychiugiahaiumtonmchinxoaychiuv cngdngin chy qua on mch in ln lt l :) (4100 cos 2 220 V u|.|

\|+ =ttv ) (6100 cos 2 2 A t i|.|

\| =tt , vit tnh bnggiy(s). a)Xcnhgitrcci,tnsgc,chuk,tns,phabanucainpgiahai u on mch. b)Xcnhgitrcci,tnsgc,chuk,tns,phabanucadnginchy trong on mch. c)Xcnhlchphagiainpgiahaiuonmchvcngdngin chytrong on mch. Bi gii : a)Tbiuthcinp:) (4100 cos 2 220 V u|.|

\|+ =tt ,ttnhbnggiy(s),tasuyragi trcci,tnsgc,chuk,tns,phabanucainpgiahaiuonmchln lt l : 2 2200 = UV~ 311 V = 100 rad/s 314 rad/s 02 , 01002 2= = =ttetTs 5002 , 01 1= = =TfHz 4t =u rad b)Tbiuthccngdngin:) (6100 cos 2 2 A t i |.|

\| =tt ,ttnh bnggiy (s), ta suyragitrcci,tnsgc,chuk,tns,phabanucadng in chy trong on mchln lt l : 2 20 = IA~ 2,83 A = 100 rad/s 314 rad/s 02 , 01002 2= = =ttetTs 5002 , 01 1= = =TfHz

6t =i rad c)lchphagiainpugiahaiu on mch v cng i ca dng in chy trong on mchl : 1256 4t t t =|.|

\| = =i u rad= 750 Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang5 Nhvy,trongtrnghpnyhiuinthgiahaiuonmchnhanhphahn dngin chytrong mchmt gc 750. Bi3:Dnginxoaychiuchyquamtonmchccngbiniiuho theo thi gianc m t bng th hnhdi y. a)Xc nh bin, chu k vtn s ca dngin. b) th ct trc tungti im c to bao nhiu? Bi gii : a)BinchnhlgitrcciI0cacng dng in. Da vo th ta c bin ca dngin nyl : I0 = 4 A. Tithiim2,5.10-2s,dnginc cng tc thi bng 4 A. Thi im k tip m dngin c cng tc thi bng4 Al 2,25.10-2 s. Do chu k ca dngin nyl : T = 2,25.10-2 0,25.10-2 = 2.10-2 s Tns ca dngin nyl : 5010 . 21 12 = = =TfHz b)Biu thc cng dngin xoaychiu nyc dng: ) cos(0 it I i e + =Tns gc cadngin nyl : t t t e 100 50 . 2 2 = = = frad/s Tithi im t = 0,25.10-2 s, dng in c cng tc thi i = I0 = 4 A,nn suyra : 0 0) 0 . 100 cos( I Ii = + tHay14cos =|.|

\|+it Suyra : 4t =i rad Do biu thc cng ca dngin nyl : ) (4100 cos 4 ) (4100 cos0A t A t I i|.|

\| =|.|

\| =ttttTithi im t = 0 th dngin c cng tc thi l : 2 2242) (40 . 100 cos00= = =|.|

\| =IA I ittA83 , 2 ~A Vy th ct trc tungti im c to (0 s,2 2A). t (10-2 s) i (A) 0 + 4 - 4 0,250,751,251,752,252,753,25 Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang6 Bi4:Biuthc in p xoay chiu gia hai u mt on mch v cng dng in xoaychiuchyquaonmchlnltl:( ) ) ( 100 cos 2 220 V t u t = v ( ) ) ( 25 , 0 100 cos 2 A t i + = t ,vittnhbnggiy(s).Tnhinphiudnggiahaiuon mchvcng hiu dngcadngin chyquaonmch. Bi gii : in phiu dnggiahai uon mchl : 22022 22020= = =UUV Cng hiu dngca dngin xoaychiu chyquaon mchl : 22220= = =IIA41 , 1 ~A Bi5:Biuthccngdnginxoaychiuchyquamtonmchl ) )( 100 cos(0A t I i t = ,viI0>0vttnhbng giy (s). Tnh t lc 0 s, xc nh thi im u tin mdngin c cng tc thi bngcng hiu dng? Bi gii : Cch 1 : Khi dngin c cng tc thi bngcng hiu dng,nghal : 2) 100 cos(00It I i = = t Suyra :4cos21) 100 cos(tt = = t hayttt 24100 k t + = ,Z k eDo : 5014001k t + = ,Z k eTachn k nguynsao cho t c gi tr dngb nht. Vik = 0 th t c gi tr dngb nhtbng 4001 s. Vytnhtlc 0 s, thi im u tin m dng in c cng tc thi bng cng hiu dngl 4001 s. Cch2:Biuthccngdngin) )( 100 cos(0A t I i t = gingvmttonhcvi biuthcli ) cos( t A x e =ca cht im dao ng c iu ho. Do , tnh t lc 0 s, tm thiimutindnginccngtcthibngcnghiudng 20II i = =cnggingnhtnht lc 0 s, tm thi im u tin cht im dao ng c iu ho c li 2Ax = .Vphabanucadaongbng0,nghallc0sthchtimangv trgiihnx= A, nn thi im cn tm chnh bng thi gian ngn nht cht im i t v trgiihnx=Anvtrcli 2Ax = .Tasdngtnhchthnhchiuca mt cht Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang7 imchuynngtrnulnmtngthngnmtrongmtphngquolmtdao ng iu hovicngchu k gii bi tonny. Thigianngnnhtchtimdaongiuho chuyn ng t v tr c li x = A nvtr c li 2Ax =(t P n D) chnh bng thi gian cht im chuyn ng trn u vicngchu k i t P n Q theo cungtrn PQ. TamgicODQvungtiDvcOQ=A, 2AOD =nnta c : 22cos = =OQODoSuyra :4to =rad Thigianchtimchuynngtrnu i t P n Q theo cungtrnPQ l : e eteo414= = = tTrong biu thc ca dng in, th tn s gc = 100rad/s nn ta suy ra tnh t lc 0 s th thi im utin mdngin c cng tc thi bngcng hiu dngl : 4001100 . 4 4= = =ttetts Bi 6. Dng in xoay chiu chy qua mt on mch c biu thc) )( 100 cos( 2 2 A t i t = , ttnhbnggiy(s).Vitbiuthcinpugiahaiuonmch,bitinpnysm phagc 3t so vidngin vc tr hiu dngl 12 V. Bi gii : Biu thc cng dngin chyquaon mch: ) )( 100 cos( 2 2 A t i t = , t tnh bnggiy(s). Biu thc in pgiahai uon mchc dng: ) cos(0 e + = t U uDnginichyquaonmchbinthin iu ho cng tn s vi in p gia hai u on mchnn tns gc ca in p u l : t e 100 =rad/s Bin ca in pu l : 2 12 20= =U UV in pu sm phahndngin i mt gc 3t nn phaca in pu l : |.|

\|+3100tttrad Vybiu thc in p u giahaiu on mchl : Ox + A 2A P Q (C) D Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang8 ) (3100 cos 2 12 V t u |.|

\|+ =tt , t tnh bnggiy(s) Bi7.Dnginxoaychiuhnhsinchyquamtonmchcbiuthc |.|

\|= tTI it 2cos0,viI0lbinvTlchukcadngin.Xcnhinlng chuyn quatit din thngca dydnon mchtrong thi gianbng a)mt phnt chu k dngin tnht thi im 0 s. b)mt phnhaichu k dngin tnht thi im 0 s. Bi gii : Cngicadnginchytrongdydnbngohmbcnhtcainlngq chuynquatit din thngcadydntheo thi giant : ) ('tqdtdqi = =Suyra in lngchuynquatit din thngca dydntrong thi gianrt b dt l : dq = idt a)inlngchuynquatitdinthngcadydntrongthigianbngT41tnht thi im 0 s l : dt tTI dt tTI qT T} }|.|

\|=|.|

\|=4004002cos2cost t tt tttt 20 .2sin4.2sin2.2sin2.00400T ITTTTI tTTI qT=|.|

\||.|

\|=|.|

\|= b)inlngchuynquatitdinthngcadydntrongthigianbngT21tnht thi im 0 s l : dt tTI dt tTI qT T} }|.|

\|=|.|

\|=2002002cos2cost t 0 0 .2sin2.2sin2.2sin2.0200=|.|

\||.|

\|=|.|

\|=TTTTI tTTI qTt tttt Lu:Cchmiuhocdng) cos( e + = t A x hoc) sin( e + = t A x thtchphn cantheobintvicntrnvcndichnhnhaumtlngbngchuk et 2= T ca n hoc bngmt s nguynchuk can th bng0. Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang9 C. CU HI V BITP TRC NGHIM Cu 1: Nguyntc to ra dngin xoaychiu datrn A. t trngquay.B. hin tngquangin. C. hin tngt cm.D. hin tngcm ngin t. Cu2:KhungdykimloiphngcdintchS,cNvngdy,quayuvi tc gc quanhtrcvunggcvingsccamtt trng uB. Chn gc thi gian t = 0 s l lcphptuynncakhungdycchiutrngvichiucavectcmngtB.Biu thc xc nh t thng| quakhungdyl A.) sin( t NBS e | = .B.) cos( t NBS e | = .C.) sin( t NBS e e | = .D.) cos( t NBS e e | = . Cu3:KhungdykimloiphngcdintchS=50cm2,cN=100vngdy,quayu vitc50vng/giyquanhtrcvunggcvingscca mt t trng u B = 0,1 T.Chngcthigiant=0sllcphptuynncakhungdycchiutrngvichiu ca vectcm ngtB. Biu thc xcnh t thng| quakhungdyl A.Wb) )( 100 sin( 05 , 0 t t | = .B.Wb) )( 100 sin( 500 t t | = . C.Wb) )( 100 cos( 05 , 0 t t | = .D.Wb) )( 100 cos( 500 t t | = . Cu4:KhungdykimloiphngcdintchS,cNvngdy,quayuvi tc gc quanhtrcvunggcvingsccamtt trng uB. Chn gc thi gian t = 0 s l lcphptuynncakhungdycchiutrngvichiucavectcmngtB.Biu thc xc nh sutin ng cm nge xuthintrong khungdyl A.) sin( t NBS e e = .B.) cos( t NBS e e = .C.) sin( t NBS e e e = .D.) cos( t NBS e e e = . Cu5:KhungdykimloiphngcdintchS=100cm2,cN=500vng dy, quay u vitc3000vng/phtquanhquanhtrcvunggcvingsccamtttrng uB=0,1T.Chngcthigiant=0sllcphp tuynn ca khung dy c chiu trng vichiucavectcmngtB.Biuthcxcnhsutinngcmngexuthin trong khungdyl A.V) )( 314 sin( 7 , 15 t e = .B.V) )( 314 sin( 157 t e = . C.V) )( 314 cos( 7 , 15 t e = .D.V) )( 314 cos( 157 t e = . Cu6:KhungdykimloiphngcdintchS=40cm2,c N = 1 000 vng dy, quay u vitc3000vng/phtquanhquanhtrcvunggcvingsccamtttrng u B = 0,01 T.Sutin ng cm nge xuthin trong khungdyc tr hiu dngbng A. 6,28 V.B. 8,88 V.C. 12,56 V.D. 88,8 V. Cu7:Cchnosauykhngthtoramtsutinngxoaychiu(sutinng bin i iu ho) trong mt khungdyphngkim loi ? A. Lmcho t thng quakhungdybin thin iu ho. B. Cho khungdyquayu trong mt t trngu quanhmt trc c nhnmtrong mt phngkhungdyvvunggc vingsc t trng. C. Cho khungdychuynng thngu theo phngct cc ngsc ttrngca mt t trngu. D. Cho khungdyquayu trong lng camt namchmvnhcu hnhchU (nam chmmngnga)xungquanhmt trc c nh nmtrong mt phngkhungdyvvung gc vingsc t trngca namchm. Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang10 Cu8:Phtbiunosauylngnhtkhinivinpdaongiuho(gitt l in pxoaychiu) ? A. in p daong iu ha l mt in p binthin u n theo thi gian. B. Biu thc in pdao ng iu hoc dng) cos(0 ut U u e + = , trong 0U , el nhnghngs, cn ul hngs phthuc voiu kin banu. C. in p daong iu ha l mt in p tnggimu n theo thi gian. D. in p daong iu ha l mt in p binthin tunhontheo thi gian. Cu 9: Pht biu nosau yl ng nhtkhi ni v dngin xoaychiu hnhsin ? A. Cng bin i tunhontheo thi gian. B. Chiu dngin thayi tunhontheo thi gian. C. Chiu vcng thayi u n theo thi gian. D. Chiu thayi tunhonvcng bin thin iu ho theo thi gian. Cu 10: Pht biuno sau yl ng nhtkhi ni v dngin xoaychiu hnhsin ? Dngin xoaychiu hnhsin c A. cng bin thin tunhontheo thi gian. B. cng bin thiniu ho theo thi gian. C. phabin thin tunhontheo thi gian. D. chiu dngin bin thin iu ho theo thi gian. Cu 11: Pht biuno sau yl khng ngkhini vdngin xoaychiu hnhsin ? Dngin xoaychiu hnhsin c A. chiu thayi tunhontheo thi gian. B. cng bin thiniu ho theo thi gian. C. cng trungbnhtrong mt chu k l khckhng. D. cng hiu dngbngcng cc i chia cho2 . Cu12:Khicmtdnginxoaychiu hnh sin) cos(0t I i e =chy qua mt in tr thun Rtrongthigiantkhln(et 2>> t ) th nhit lngQ to ra trn in tr R trong thi gian l A.t R I Q20= .B.Rt I Q20) 2 ( = .C.Rt I Q20= .D.Rt I Q205 , 0 = . Cu13:DnginxoaychiuchyquaintrthunR=10cbiuthc ) )( 120 cos( 2 A t i t = ,t tnh bng giy (s). Nhit lngQ to ra trn in tr trong thi gian t = 2 min l A. Q = 60 J.B. Q = 80 J.C. Q = 2 400 J.D. Q = 4 800 J. Cu14:MtdnginxoaychiuiquaintrR=25trongthigiant=120sth nhitlngtoratrnintrlQ=6000J.Cnghiudngcadnginxoay chiu nyl A. 2 A.B. 3 A.C.2A.D.3A. Cu15:Xtvtcdngtonhittrongmtthigiandithdnginxoaychiuhnhsin) cos(0 it I i e + =tngngvimt dngin khngi c cng bng A. 02I .B. 02I .C. 220I.D. 20I. Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang11 Cngcamtdnginxoaychiucbiuthc) cos(0 it I i e + = .Cnghiu dngca dngin xoaychiu nyl A. 02I I = .B. 02I I = .C. 20II = .D. 20II = . Cu16:Dnginxoaychiucbiuthc) )( 200 cos( 3 2 A t i t = ,t tnhbnggiy(s),c cng hiu dngl A. 2 A.B. 2 3 A.C.3A.D.6A. Cu 17: Chnphtbiu ngkhini vcng hiu dngca dngin xoaychiu. A. Cng hiu dngo c bngampek mt chiu. B. Gi tr ca cng hiu dngo c bngampek xoaychiu. C. Cng hiu dngcadngin xoaychiu bngcng dngin khngi. D. Gi tr ca cng hiu dngc tnhbi cng thc 02I I = , trong 0Il cng cc i cadngin xoaychiu. Cu18:Mtdnginxoaychiuhnhsincbiuthc) (3100 cos A t i|.|

\|+ =tt ,t tnhbnggiy(s). Kt lunno sauy lkhng ng? A. Tns ca dngin l 50 Hz. B. Chuk ca dngin l 0,02 s. C. Bin cadngin l 1 A. D. Cng hiu dngcadngin l2A. Cu19:Chodnginxoaychiucbiuthc) (3100 cos 2 A t i |.|

\|+ =tt ,t tnh bng giy (s). Tronggiyu tin tnh t 0 s, dngin xoaychiu nyi chiu c myln? A. 314 ln.B. 50 ln.C. 100 ln.D. 200 ln. Cu20:Dnginxoaychiuchyquamtonmchcbiuthc ) (3100 cos 2 5 A t i |.|

\| =tt ,t tnhbnggiy(s).Vothiimt=3001sthdnginchy trong on mchc cng A. cc i.B. cc tiu. C. bngkhng.D. bngcng hiu dng. Cu21:Dnginxoaychiuchyquamtonmchcbiuthc ) (2100 cos 2 2 A t i |.|

\| =tt ,t tnhbnggiy(s).Vothiimt=4001sthdnginchy trong on mchc cng A. cc i.B. cc tiu. C. bngkhng.D. bngcng hiu dng. Cu22:Dnginxoay chiu chy qua mt on mch c biu thc( ) ) ( 100 cos 2 2 A t i t = ,ttnhbnggiy(s).Vothiimt =3001 s th dng in chy trong on mch c cng tc thi bngbao nhiuvcng dngin angtnghayanggim? Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang12 A. 1,0 A vanggim.B. 1,0 Avangtng. C.2vangtng.D.2vanggim. Cu 23: Gitr ca in phiu dngtrong mngin dndng nc ta A. bng110 V.B. bng220 V. C. thayi t - 220 Vn + 220 V.D. thayi t - 110 Vn + 110 V. Cu24:inpgiahaiumtonmchcbiuthc) )( 100 cos( 2 110 V t u t = ,t tnh bnggiy(s). in phiu dnggiahaiuca on mchnyl A. 110 V.B.2 110V.C. 220 V.D.2 220V. Cu 25: Vnk vampek xoaychiu l nhngdngc dng o A. gi tr tc thi ca in pvcng dngin xoaychiu. B. gi tr trungbnhca in p vcng dngin xoaychiu. C. gi tr cc i cain pvcng dngin xoaychiu. D. gi tr hiu dngca in p vcng dngin xoaychiu. Cu26:Dnginchyqua mt on mch c biu thc) 5 , 0 100 cos(0t t = t I i ,ttnh bng giy (s). Trong khong thi gian t 0 (s) n 0,01 (s), cng tc thi ca dng in c gi tr bng0,5I0 vonhngthi im A.) (4001sv) (4002s .B.) (2001sv) (2003s . C.) (4001sv) (4003s .D.) (6001sv) (6005s . Cu27:Dnginchyquamtonmchcbiuthc) 100 cos(0t I i t = ,t tnhbnggiy (s).Trongkhongthigiant0(s)n0,01(s),cng tc thi ca dng in c gi tr bng0,5I0 vothi im A.) (3002s .B.) (3001s .C.) (6001s .D.) (3007s . Cu28:inpxoaychiugiahaiumtonmchbiniiuhotheothigian cmtbngthhnhdiy.Biuthcinptcthi gia hai u on mch nyl A.) (32100 cos 200 V t u |.|

\| =tt .B.) (32100 cos 200 V t u |.|

\|+ =tt . t (10-2 s) u (V) + 200 31 65 34 611 37 617 310 - 200 - 100 0 Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang13 C.) (65100 cos 200 V t u |.|

\| =tt .D.) (65100 cos 200 V t u |.|

\|+ =tt . Cu29:inpgiahaiumtonmchcbiuthc) (2100 cos 2 220 V t u |.|

\| =tt ,ttnhbnggiy(s).Tnhtthiim0s,tmthiimutininpcgitrtcthi bnggitr hiu dngvin panggim? A.) (4001s .B.) (4003s .C.) (6001s .D.) (3002s . Cu30:inpgiahaiumtonmchcbiuthc) (2100 cos 2 220 V t u |.|

\| =tt ,ttnhbnggiy(s).Timtthiim) (1s t no in p ang gim v c gi tr tc thi l ) ( 2 110 V .Hivothiim) ( 005 , 0 ) ( ) (1 2s s t s t + = thinpcgitrtcthibngbao nhiu? A.) ( 3 110 V .B.) ( 3 110 V + .C.) ( 6 110 V .D.) ( 6 110 V + . Cu31:Dnginxoaychiuchyquamton mch c cng bin i iu ho theo thigiancmtbngthhnhdiy.Biuthccngtcthicadng in xoaychiu chyquaon mchin nyl A.) (32100 cos 2 A t i|.|

\| =tt .B.) (32100 cos 2 A t i|.|

\|+ =tt . C.) (43100 cos 2 A t i|.|

\| =tt .D.) (43100 cos 2 A t i|.|

\|+ =tt . Cu32:Dnginxoaychiuchyquamtonmchcbiu thc( ) ) ( 120 cos 2 A t i t = ,ttnhbnggiy(s).Tronggiyutintnhtthiim0s,dnginccngbng khngc myln? A. 50 ln.B. 60 ln.C. 100 ln.D. 120 ln. Cu33:Mtnneontdi in p xoay chiu c gi tr hiu dng) ( 220 V U =v tn s ) ( 50 Hz f = .Bitnsngkhiinp gia hai cc ca n khng nh hn) ( 200V . Hi trong mt giyc bao nhiu lnn sng? A. 2 ln.B. 50 ln.C. 100 ln.D. 200 ln. t (10-2 s) i (A) 0 + 2 - 2 0,25 0,751,251,75 2,25 2,75 Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang14 Cu34:Mtnincghi110V75Wcdngvidnginxoay chiu c tn s ) ( 50 Hz f = .Chobitbngnsngbnhthng.inpccigiahaiucadytc bngn l A.) ( 110 V .B.) ( 2 110 V .C.) ( 220V .D.) ( 2 220 V . Cu35:Mtnneontdi in p xoay chiu c gi tr hiu dng) ( 220 V U =v tn s ) ( 50 Hz f = .Bitnsngkhiinpgiahai cc ca n khng nh hn) ( 6 , 155 V (coi bng ) ( 2 110 V ).Tsgiathigiann sng v thi gian n tt trong mt chu k ca dng in l A.1 : 1 .B.1 : 2 .C.2 : 1 .D.5 : 2 . Cu36:Dnginxoaychiuchyquamtonmchcbiuthc ) (2100 sin 2 A t i |.|

\|+ =tt ,t tnhbnggiy(s).Tnhtlc) ( 0 s ,thiimutinmdng in c cng bngcng hiu dngl A.) (1001s .B.) (3001s .C.) (4001s .D.) (6001s . Cu37:Hnhbnlthbiudins binicainpgiahaiu mt on mchxoaychiuvcngdngin chytrongonmchtheothigian. Ktlunnosauylngkhiniv lch phagiau (t) vi (t) ? A. u (t) chmphaso vii (t) mt gc 2t rad. B. u (t) nhanhphaso vii (t) mt gc 2t rad. C. u (t) chmphaso vii (t) mt gc 32t rad. D. u (t) nhanhphaso vii (t) mt gc 32t rad. Cu38:Dnginxoaychiuchyquamtonmchcbiu thc( ) ) ( 100 cos 5 , 0 A t i t = ,ttnhbnggiy(s).Tnhtlc) ( 0 s ,dnginccngbngkhnglnthbavothi im A.) (2001s .B.) (2003s .C.) (2005s .D.) (2009s . Cu39:Dnginchyquamtonmchcbiuthc) (2100 cos 2 A t i |.|

\| =tt ,t tnh bnggiy(s).Trongkhongthigiant0(s)n 0,01 (s), cng tc thi ca dng in c gi tr bngcng hiu dngvonhngthi im A.) (6001sv) (6003s .B.) (2001sv) (2003s . u, i t u(t) i(t) 0 Dng in xoay chiu Ch I. i cng v dngin xoay chiu Thy inh Trng Ngha, gio vin Vtl,trng THPT chuyn L Khit - Qung NgiTrang15 C.) (4001sv) (4003s .D.) (6001sv) (6005s . Cu40:Dnginxoaychiuchyquamtonmchcbiuthc ) (2100 cos 2 2 A t i |.|

\| =tt ,t tnhbnggiy(s).Vomtthiimno,dnginang tngvccngtcthibngcnghiudng th khong thi gian ngn nht sau dngin li c cng tc thi bngcng hiu dngnhnganggiml A.) (4001s .B.) (2001s .C.) (1002s .D.) (3001s . Cu41:Vocngmtthiimno,haidnginxoaychiu) cos(1 0 1 e + = t I i v ) cos(2 0 2 e + = t I i uccnggitrtcthil 02 5 , 0 I nhngmtdnginanggim, cn mt dngin angtng.Kt lunno sauy l ng? A. Hai dngin daong cngpha. B. Hai dngin daong ngcpha. C. Hai dngin daong lch phanhaugc 1200. D. Hai dngin daong vungpha(lch phanhaugc 900). Cu42:Vocngmtthiimno,haidnginxoaychiu) cos(1 0 1 e + = t I i v ) cos(2 0 2 e + = t I i uccnggitrtc thi l 05 , 0 Inhng mt dng in ang gim, cn mt dngin angtng.Hai dngin nylch phanhaumt gc bng A. 6t.B. 32t.C. 65t.D. 34t. Cu43:Dnginxoaychiuchyquamtonmchcbiuthc ) (2100 cos 2 2 A t i |.|

\| =tt ,t tnhbnggiy(s).Vomtthiimno,dnginang ccngtcthibng) ( 2 2 A thsautnhtl bao lu dng in c cng tc thi bng) ( 6 A? A.) (6001s .B.) (3001s .C.) (6005s .D.) (3002s . Cu44:Dnginxoaychiuhnhsinchyquamtonmchcbiuthccbiuthc cngl |.|

\| =2cos0tet I i ,I0>0.Tnhtlc) ( 0 s t = ,inlngchuynquatitdin thngca dydnca on mch trong thi gianbngnachu k cadngin l A. 0.B. et02I.C. 20etI.D. e02I. Cu45:Dnginxoaychiuhnhsinchyquamtonmchcbiuthccngl ) cos(0 it I i e + = ,I0>0.inlngchuynquatitdinthngcadydnonmch trong thi gianbngchu k cadngin l A. 0.B. et02I.C. 20etI.D. e02I. v