03 Cau 45 M?ich difn gom bien trd R noi tiep cupn day thuan cam L = — H Di?n ap xoay chieu hai dau m^ch c6 d?ing u = U V2 coslOOTrt Ban dau bien tra R c6 gia trj 40 Q, sau tSng gia trj R cua bien tra thi cong suat toa nhi^t tren bien trasg A giam B ting C tSng roi giam D giam roi ting , Cau 46 Theo thuyet Big Bang, hi^n vu try A khong thay doi v^t chat dupe t^o lien tyc B dang a trying thai djnh C dang nd va loSng dan D dang CO l^i va dong d$e dan Cau 47 Biet toe dp 4nh sang chan khong la c va khoi lupng nghi cua mpt h^t la m Theo thuyet tuong doi h^p eua Anh-xtanh, h^t ehuyen dpng vori toe dp V thi khoi lupng cua no la A m C m 1+- 1-> V V' c2 D m 1— ^ Cau 48 Mpt ngu6ri canh sat dung a ben ducmg phat hoi coi c6 tan so f = 800 Hz ve phia mpt oto vira ch^y qua truac m^t vai toe dp 35 m/s Toe dp am khong la 340 m/s Am ma tai xe nh$n dupe eo tan so A 676 Hz B 780 Hz C 718 Hz D 824 Hz Hir6NG DAN GIAI Cau D V^it dao dpng dieu hoa qua vj tri can bang toe dp e^e d?ii, gia toe bSng Cau B May phat dif n xoay chieu kieu cam ung c6 phan cam la phan t^o tu truang va phan ung la phan t^o suat di^n dpng Cau3.C Chuki:T = 27tVLC,v6iIo = (oQo= - ^ Q O ^ V L C = ^ VLC =>T = t ^ h I ^0 Cau B S\ epng huomg ca xay tan so l\rc eu5ng buc bSng tan so dao dpng rieng eua h? Cau B Tir T = 2% — => Chu ki dao dpng b^ cua eon lac dan phy thupe gia toe trpng truang g va chieu dai day treo eon lac Cfiu C Con lac 16 xo dao dpng dieu hoa vai tan so f, the nang cua lac sS bien thien v6i tan so f = 2f 100 Cau C Trong cac nha may difn nguyen tu ho?it dpng binh thucmg hifn nay, phan ung xay 16 phan ung h^t nhan cua nha may de cung cap nSng lugfng cho nha may ho^t dgng la phan ung phan h ^ h day chuyen dugc khong che a muc toi h^n Cau A Khi electron chuyen tu quy d^o M tra ve cac quy d?io ben se phat mpt buc thupc day Banme, hai biic thuQC day Laiman Cau B Quang duong ngSn nhat v^t di ^ T la A Cau 10 D Tia tu ngo^i va tia X deu c6 ban chat la song di?n tu, c6 buoc song dai ngin khac nhau, nen c6 kha ning dam xuyen khac Cau 11 A Hai nguon ket hgrp A va B dao dpng voi tan so f = 15 Hz va cimg pha T^i M : di = 16 cm va d2 = 20 cm, song c6 bien dp eye tieu Giua M va duong trung tryc ciia AB c6 day eye d^i => M nam tren eye tieu thu nen d2 - di = 2,5> => X = 1,6 cm => T6c dp truyen song tren mjt nuoc: v = Xf= 24 cm/s Cau 12 D H^it so cap luon ben vung la y sai Cau 13 B AB = c m ; f = H z Tren day eo song dung va rung miii => k = Tu ^ = - = 60=>? = 40 cm => Toe dp truyen song tren day: v = A,f = 2000 cm/s = 20 m/s Cau 14 B Song CO hpc khong truyen dupe chan khong Cau 15 D Trong mach difn xoay ehieu RLC khong phan nhanh: Khi C = — : r ^ — 27tfL = —^-— 471 f L 27tfC ZI^=ZQ=> Trong m^ch eo cpng huong nen: + + + + Cuong dp dong di^n cung pha vai di^n ap hai dau do^n m^ch Difn ap hifu dyng hai dau di^n tra R d^t gia trj eye d?ii Cong suit tieu thy trung binh m^eh d^t gia trj eye d^i Difn ap hifu dyng giOa hai dau ty di^n d^t gia trj eye d?i la y sai 101 Cau 16 B RP^ Cong suat hao phi tren duong day tai: AP = U^cos^cp => De giam cong suat hao phi tren duong day tai di^n, nguai ta sg + tang tiet di$n cua day dan de R giam + tang di|n ap U a nai truyen di + tang h§ so cong su4t m^ich truygn tai Cau 17 B 11 ZL = LCO = 50 n ; u = 180cos(1007rt+-)V=> 1^=^ = 3,6 A ZL Cufirng dp dong di^n qua cupn day chgm pha so voi u nen: i = 3,6cos(100jrt 3n ) A Cau 18 A 0,04 n va L = 71 ; f = 50 Hz ZL = Q R= T u U = 10V;1 = A =>Z = R + ( Z L - Z C ) ^ = y = = > | Z L - Z C | = => |4 - Zcl = => Zc = 8Q => C = ^ — = 398 (lo^i nghi^m Zc = 0) Zc© Cau 19 A Khi cuong dp am tang gap 100 Ian thi muc cuong dp am s6 tang them 20 dB (long quat: Khi cu&ng dq dm tang gap l(f idn thi muc cuong dip dm se tang them lO.n dB) Cau 20 C R = 40fl;r= 10fi;u= 110coscot(V) =>U = 55V2 V Dien dp gi&a hai ban ty di?n Ifch pha 90° so vdi u u cung pha i nen m?ich c6 cpng huong Cong suat tieu th\ cua cupn day sS la: P = rl?, = rU^ = 24,2 W (R + r)2 Cau 21 C Phucmg trinh ph6ng xa : ^^Na -> _°e + ^ ^ Ban dau c6 mo = 4,8 g n ^ a , khoi lupng magie t?o sau t = 15 h la Am = 2,4 g Kh6i lupng Na da phong cung bang 2,4 g (do so khoi Na va Mg bang nhau) => Khoi lupng Na l^i bang 2,4 g = 0,5mo => T = t = 15 h Sau t' = 60 h = 4T: Khoi lupng Na da phong x^: m^ = ^ = — = 0,3 g 16 => Khoi lupng magie t^o bang khoi lupng Na da ph6ng : 102 niMg = 4,8 - 0,3 = 4,5 g 22 D Khi i = ^ ^ = > W , = - L i = - - L l g = - W i i > W d = -Wr:>W, = Wd W^y 2 4 luc nSng iugmg tijr tnrcmg gap ba \hn ning lugng difn tnrong Cau 23 B Xet cac hanh tinh Mpc tinh, Thuy tinh ; Hoa tinh ; Thien Vuomg tinh Hanh tinh xa M$t Trai nhat la Thien Vuong tinh Cau 24 C Buc CO buac s6ng X = 0,21 (im 1^ tia tix ngo^ii Cau 25 D Be rpng cua 10 khoang van dirgrc la 1,6 cm = 16 mm => 10i= 16 =>i= 1,6 mm X T^i diem A c6 x = mm: — = — = 2,5=^M la van toi thu ke tir van sang i 1,6 chinh gifta Cau 26 D Chiet suat cua chat lam l ^ g kinh k h i c doi v6i cac &nh sang dom s^c khac Cau 27 C Theo thuyet lugrng tu, ta c6 cam giac chiim sang lien tyc la mpt chum sang du yeu cung chua mpt so rat lom lugrng tu anh sang Cau 28 C X = 0,5 ^m = 0,5.10"^ mm; a = mm; D = m = 2.10^ mm Khotegvan: i = — =0,5 mm a X6t: - = ^ = 15,6 => So van sang la 15 va so van toi la 16 0,5 Cau 29 B H^t nhan cang ben viJng c6 nSng lugrng lien ket rieng cang Idn Cau 30 A Quang lien tyc cua dnh sdng trdng gom mgt dai sang bien thien lien tyc tu den tim Cau 31 B Phan ung ^H + ^H ^ 2^e + gn la phan umg nhi^t h?ich nen toa n5ng lugrng Phan ung '^C ' N + "e 1^ phan umg phong x?i nen toa nSng lugmg Phin umg 4}H -> jHe + ^.^e"^ la phan ung nhi^t h?ich nen toa nSng lugmg => Phan ung jHe + -> 'gO + {p la phan umg thu nSng lugmg Cau 32 C Tia hong ngo^i gay mpt so phan ung hoa hgc 103 Cau Cau 33 D Chu ki T = s; H6n bi chuyen dpng tren mpt cung tron dai cm => Bien dp So' = cm => Thai gian de hon bi di dugrc cm = So ke tCr vj tri can bang ia 0,25T = 0,75 s Cau 34 B Tir £ = k-=^X = — =^X m max k Khoang each giOa byng va nut song ke co gia trj Ion nhat bSng ^ = lm Cau 35 B U = Uc = 2UL.^ H? so cong suat cua m^eh dif n : cos(p = u u V3 u Cau 36 D Tia X CO ban chat giong v6i ban chat tia hong ngo^i Cau 37 B Tu X = C I > / L C = > A , ^ ~ C • Khi m5c t\ Ci vai L A,, = 60 m Khi mSc ty C2 vai cupn L thi A,2 = 80 m Khi mSc noi tiep Ci va C2 vai cupn L: 1 - ^ , 1 Tu — = — + — -+ • C C, 60^ 80^ A = 48 m Cau 38 D Xo = 0,5 |i.m Chieu anh sang vao catot, chiim anh sing khong gay hifn tugrng quang di?n la tia hong ngo^i (vi tia hong ngo^i eo ^ > 0,5 fxm) Cau 39 C Nang lugrng ciia lugrng tu anh sang nhd horn nSng lugrng cua lugrng tu anh sang tim Cau 40 B Qua trinh phong h?it nhan la qua trinh toa ning lugrng Cau 41 B Khi mgt v$t rin quay bien doi deu thi gia toe g6e cua v§t tin khong thay doi theo thai gian Cau 42 B Mgt v$t tin dang quay nhanh dan deu quanh mgt tryc co djnh xuyen qua v^t vai gia toe goc y Khi toe dp goc ciia v$t la co, diem M tren v^t ran each tryc quay mpt d o ^ R ^ CO gia toe a = R-^y^ +00"* 104 Cau43.B Tic dving vao mpt v$t ran dang dumg yen, c6 tryc quay c6 djnh xuyen qua v§t, mpt Ivrc F Bo qua mpi l\rc can V$t ran se dung yen i\rc F c6 gia song song tr\ic quay Cau 44 C c o = 30rad/s;a) = ; t = 10 s o Giatocgoc: Y ^ ^ ~ ^ ° =-3 rad/sl Goc quay cuadTa: a- - = 150rad = 2y So vong dTa quay dugrc thoi gian quay ch^m dan la: a n = — = 23,88 vong 2n Cau 45 A ZL = 30 Q Cong suat toa nhi^t c\rc d?ii R = ZL = 30 Q Ban dau bien tra R c6 gia trj 40 Q => Khi tang gia trj R ciia bien tra thi cong suat toa nhi^t tren bien tra sS luon giam Cau 46 C Theo thuyet Big Bang, hi^n vu tr\ dang na va loang dan Cau 47 D Biet toe dp anh sang chan khong la c va khoi lugmg nghi cua mpt h^it la m Theo thuyet tuang doi h^p cua Anh-xtanh, h^t chuyen dpng vai toe dp v thi khoi lupng cua no la1-Cau 48 C Oe ON LUYEN TU TAI I Phan Chung cho tat ca c^c thi sinh: (32 cau, tiir cau den cau 32) Cau Doi v6i lac 16 xo nam ngang dao dpng dieu hoa: A Trpng l\rc cua Trai Dat tac d\ing len v$t anh huang den chu ki dao dpng cua v$t B Bien dp dao dpng phy thupc dp dan 16 xo vj tri can bang C Lye dan hoi tac dyng len v^t cung chinh la l\rc lam v^t dao dpng dieu hoa D Khi 16 xo CO chieu dai eye tieu thi dp Ian l\rc dan hoi tac dyng vao v$t nho nhat 105 Cau V§t dao dpng dieu hoa c6 thj nhu hinh ben Ket lu|in nao sau day sai? A Tan so dao dpng la 2,5 Hz B V$n toe v$t qua vj tri ean bSng la 1,6 em/s C Thai gian ngin nhat v$t di tir bien ve vj tri ean bSng la 0,1 s D Toe dp t^i t = eua v$t bSng Cau Con iSe 16 xo (m = 200 g; ehieu dai 16 xo a vj tri ean bSng la 30 em) dao dpng dieu hoa theo phuong thing dung vol tan so goe la 10 rad/s va bien dp A = em L\re keo ve tae dyng vao v§t 16 xo eo ehieu dai 33 em bang A 0,33 N B.0,3N C.0,6N D.0,5N Cau Mpt v$t ehuyen dpng theo phuong trinh x = - eos(27rt - ^ ) (x eo don vj la em ; t eo don vj la giay) V$t A khong dao dpng dieu hoa vi eo bien dp am B dao dpng dieu hoa voi bien dp em va eo pha ban dau la - — C dao dpng dieu hoa voi bien dp em va eo pha ban dau la ^ D dao dpng dieu hoa v6i ehu ki s va eo pha ban dau la - j Cau Mure euong dp am t?ii A la LA= 80 dB, t^i B la L B = 50 dB Gpi U va IB la euong dp am t^i A va B, ti so U /IB la A 8/5 B 5/8 C.30 D 1000 Cau Trong thi nghi^m giao thoa anh sang Y-ang: Nguon S phat hai anh sang don sSe eo buoe song A,i = 0,4 jxm va X2 = 0,6 \im Diem M eo van sang eijng mau voi van sang trung tam, t^i M la van sang b^c A eua anh sang buae song Xi B eua anh sang buae s6ng X2 C eua anh sang buae song Xi D eua anh sang buoe song X\ Cau Tia tu ngo^i A khong lam den kinh anh B khong bj nuoe hap thu C e6 tae dyng nhift D truyen dupe qua kim lo^i Cau Buae song la A quang du6ng song truyen di dupe mpt dan vj thai gian B khoang eaeh gi&a hai gpn song gan nhat C khoang each giua hai diem tren song eung eo ly dp bSng khong a cung mpt thai diem D khoang each giua hai diem gan nhat eiing tren phuong truyen song va dao dpng eiing pha 106 Cau Trong thi nghifm giao thoa song tren m$t nu6c, hai nguon ket hgrp cung pha M va N CO tan so la 15 Hz, t^i mpt diem C cdch M va N Ian lugt la 15 cm va 20 cm dao dgng v6i bien dp c\rc d^i Toe dQ truyen song tren m$t nuac c6 the la D 40 cm/s B 30 cm/s C 60 cm/s A 25cm/s Cau 10 Dung khang cua mpt m?ich xoay chieu RLC mSc noi tiep dang c6 gia trj nho hon cam khang Muon xay hi^n tugmg cgng huomg di^n m^ch, ta phai A ting di^n dung ciia ty difn B ting h§ so ty cam cua cupn day C giam dif n tra cua m^ch D giam tan so dong dif n xoay chieu Cau 11 M^ch di?n xoay chieu RLC m5c noi tiep dang c6 tinh cam khang, tSng tan so dong di^n xoay chilu thi hf so cong suat cua m^ch sg A khong thay doi B ting C giam D giam roi ting Cau 12 Dieu nao sau day la sai noi ve dpng ca khong dong bp pha? A Tir truong quay dpng ca dupe t^o tir dong difn xoay chieu cCmg pha B Dpng ca khong dong bp pha c6 cau t^o stato giong may phat di^n xoay chieu pha C Stato la phan cam va roto la phan umg D Roto hinh try c6 tac dyng nhu mpt cupn day quan tren loi thep Cau 13 Phat bieu nao sau day la sai so sanh tia Romghen (tia X ) vai tia gamma (tiay)? A H?it photon chiim tia y c6 ning lupng Idn hom h^it photon chiim tia X B Tia X CO buac song ngSn hom tia y C Tia X va tia y deu c6 ban chat la song di^n tir D Tia X va tia y deu c6 kha nSng dam xuyen qua cac v^t khong suot Cau 14 May bien ap A la thiet bj bien doi di$n ap va tan so cua dong di^n xoay chieu B CO hai cupn day dong vai so vong bSng quan tren loi thep C CO cupn day noi vai m ^ g difn xoay chieu dupe gpi la cupn thu cap D ho^t dpng dya vao hi?n tupng cam ung di?n tir Cau 15 Trong m^ch xoay chieu gom di^n tra R, cupn thuan cam L va ty C mic noi tiep vao di^n ap u = Uocoscot H | so cong suat m^ch Ion nhat A C = — O LC B u vuong pha uc C.R=|ZL-ZCI D U R = UO Cau 16 D$t vao hai dau do(in m^ich (gom di?n tra thuan va ty di^n m4c noi tiep) mpt di^n ap xoay chieu u eo gia trj hi?u dyng 100 V thi d6ng di?n qua di§n tra l?ch pha 60° so vai di?n ap u Di^n ap hif u dyng gi&a hai ban ty di?n bSng A 100^/3V B 50 V C SOVJv D ^ V yf3 107 Cau 17 Xet phong x?i: X Y + a Ta c6: A my + nia = mx B Phan ung thu ning lugrng C n^t Y ben Hon h^t X D H^t a la nguyen tu Heli Cau 18 Khi noi ve di^n tir truomg, phat bieu nao sau day la sai ? A Duong cam ung tir ciia tu truong xoay la cac duong cong kin bao quanh cac duong sue di§n truong B Mpt tir truomg bien thien theo thoi gian sinh mpt di^n truCmg xoiy C Mpt di^n truong bien thien theo thoi gian sinh mpt tir truong xoay D Duong sue difn truong cua di$n truong xoay giong nhu duomg sue di^n truong mpt di^n tich dung yen gay Cau 19 Khi noi ve song di^n tir, phat bieu nao sau day la sai ? A Song di^n tu chi truyen dupe moi truomg v?it chat dan hoi B Song di?n tu la song ngang C Song dif n tir Ian truyen chan khong voi v$n toe c « 3.10* m/s D Song di^n tir bj phan x^i g$p m$t phan each giua hai moi truomg Cau 20 Phat bieu nao sau day la diing noi ve quang pho? A Quang lien tyc cua nguon sang nao thi phy thupc phan cau t^o cua nguon sang ay B M6i nguyen to hoa hpc d tr^ng thai hay hoi nong sang duoi ap suat thap cho mpt quang v^ich rieng, d$c trung cho nguyen to C De thu dupe quang hap thy thi nhi^t dp ciia dam hay hoi hap thy phai cao hon nhi^t dp cua nguon sang phat quang lieii tyc D Quang hap thy la quang cua anh sang mpt v^t r4n phat v^t dupe nung nong Cau 21 The nSng cua ISc don dao dpng dieu hoa A bang voi nSng lupng dao dpng v^t n^ng o bien B eye d^ii v^t qua vj tri can bSng C luon khong doi vi quy d^o v$t n^ng dupe coi la thing D khong phy thupc goc Ifch cua day treo Cau 22 Trong cac phat bieu sau day, phat bieu nao la sai? A Anh sang trSng la t6ng hpp (hon hpp) ciia nhieu anh sang don sic c6 mau bien thien lien tyc tu toi tim B Anh sang don sSc la anh sang khong bj tan sic di qua lang kinh C Anh sang M$t Troi phat 1^ anh sang don sic vi no c6 mau trSng D Hi$n tupmg chum sang tring, di qua mpt lang kinh, bj tach nhieu chiim sang c6 mau sac khac la hi^n tupng tan sdc anh sang Cau 23 Tinh chat noi b?it ciia tia X la A tac dyng m^mh len kinh anh B lam phat quang mpt so chat C lam Ion hoa khong D kha nang dam xuyen m^nh 108 Cau 24 De chu ki ban r5 cua mpt ch4t phong A, nguai ta dung may dem xung Trong Ian dem thu nhat may ghi dugrc 340 xung phut Sau ngay, may dem chi ghi dugrc 112 xung phut Chu ki ban cua ch4t phong x? A la A.30gia B 5gior C 7,5 gicr D 15 gior Cau 25 Trong thi nghi?m giao thoa anh sang Y - ang: Gpi i la khoang van tren man thi khoang each tir van sang thu den van toi thu 10 a hai ben van sang trung tarn la A 12i B 10,5i C l l , i D H i Cau 26 Hi^n tugmg quang di?n la hi?n tugmg A giam m^nh dif n tra suat cua chat ban dan h\u bSng chum sang thich B giam m ^ h difn tra cua mpt so kirn lo^i dugrc chieu bSng chum sang thich hgrp C chat ban dan dugrc chieu sang bSng chum sang thich hgrp s6 ngimg d i n difn D difn tra cua kim lo^i ting len bj chieu sang bang chiim sang thich hgrp Cau 27 S\ phat quan§ A chi xay vai chat rin B chi xay vai chat long C khong xay vai chat D chi xay vai mgt so chat Cau 28 Trong nguyen tu hidro, electron chuyen tir quy d^o Q (c6 muc nSng lugng E = - 0,28 eV) ve quy d^io L ( c6 muc nSng lugmg E2 = - 3,40 eV ) no phat mgt photon c6 ning lugrng e la bao nhieu? Buac song tuang umg vai photon thugc viing song di^n tu nao? A e = - 3,12 eV ; anh sang nhin thay B = - 3,12 eV ; hong ngo^i C E = 3,68 eV; anh sang nhin thay D e = , e V ; t u n g o i Cau 29 Song ca truyen mgt moi truong dgc theo tryc Ox vai phuang trinh u = cos(20t - 4x) (cm) (x tinh bang met, t tinh bSng giay) Toe dg truyen song moi truong tren bang A 5m/s B 50cm/s C 40 cm/s/ ^ D m/s/ Cau 30 Cho m^ch xoay chieu gom R - L - C mic noi t i l p Ggi U la difn dp hifu d\ing hai dau m^ich ; UR , U L va Uc la difn Ap hifu d\ing hai dau R , L va C Dieu nao sau day khong the xay ra? A U R > U B U L > U C.UR>UC D U = UR = U L= U C Cau 31 Cho phan ung h^t nhan: 53 A l + a ^ n + X H^t nhan X t^o ttr phan ung 1^ A.ilS ^ B.?^Mg C.f.Si D.3°P Cau 32 Mgt lugrng chat phong x? X, t^i thai diem to c6 No h^t: T^i t = to + 24 ngky thi so h^t c6n l^i la N = 12,5% No, nhu v$y t^i thai diem t ' = t© + so h^t c6n l^i 1^ A N ' = 25%No B N ' = 50%No C N ' = 75%No D N ' = 37,5%No 109 B Theo chiroTig trinh nang cao: (8 cau, tir cau 41 den cau 48) Cau 41) Mgt vat rSn dang quay deu quanh tryc c6 djnh vai toe dp goc 20 vong/phut va momen dgng lugng ciia v^t r4n doi vai tryc quay c6 dp Ian bang - kg.m'/s Dgng nang quay cua v^t rkn bang: A I J B 3J C.4J D 5J Cau 42) Chieu Ian lugt vao mpt tam kim lo^i cac buc c6 buac song va X2 = 0,4X\ thi dgng nSng ban dau cvrc d^i cua electron but khoi tam la W, va W2 = 3Wi Giai h?n quang di?n cua kim lo^i la XQ Ti so T^vai Xi bang A B 1,5 C.4 D Cau 43) Mgt h^t c6 dgng lugng tuang doi tinh gap Ian dgng lugng c6 dien (tinh theo Ca hpc Niu-tan) Toe dp cua h^t doi vai hf quy chieu durng yen la A 0,50c B 0,60c C 0,80e D 0,87c Cau 44) Cho iSng ki'nh c6 goc chiet quang A = 45° dat khong Chieu chum tia sang song song h?p (anh sang hon hgp gom anh sang : do, vang, lam va tim) theo phuang vuong goc vai m^t ben thu nhat eua lang kinh Cho biet chiet suat eua iSng kinh doi vai anh sang mau l^ic la n = V2 Nhu v^y, 16 khoi m^t ben thu hai ciia lang kinh A gom cae tia do, vang va lam B chi c6 tia d6 va vang C chi CO tiatim D chi c6 tia Cau 45) Mpt lac v^t ly eo khoi lugmg m, momen quan tinh doi vai trye quay la 1, trpng tam G ciia vgt each trye quay Q mpt doan d Tan so goc lac dao dgng dieu hoa la A.co=/^ d B.co=/^ • VI C.co=F " Vgd D.co = • V , ^ d Cau 46) Mgt lac 16 xo gom v^t njng c6 khoi lugng 200 g, dg eimg 16 xo 80 N/m Kich thich de lac dao dgng dieu h6a vai nang lugng bang 6,4.10"^ J 86 qua ma sat Gia toe eye d^i ciia v^t c6 gia trj la A 16cm/s^ B 3,2cm/s^ C 0,8 m/s^ D 16m/s^ Cau 47) Trong truomg hgp nao sau day thi am may thu ghi nhan duge c6 tan so Ion han tan so ciia am nguon phat ra? A May thu chuyen dgng xa nguon am dung yen B May thu chuyen dgng cung chieu va eimg toe dg vai nguon am C Nguon am chuyen dgng xa may thu dung yen D May thu chuyen dgng l^i gan nguon am dimg yen Cau 48) Kim lo^i dung lam catot eua mgt te bao quang di?n eo cong thoat electron A = 2,2 eV Chieu vao catot mgt buc xg eo buac song X Cho h = 6,625.10"^''j.s; c = 3.10Ws ; e = 1,6.10'''C De tri?t tieu d6ng quang di^n, nguai ta d$t vao anot va catot mgt hifu difn the ham Uh = 0,4 V Buac song A X = 0,477 ^m B.X = 0,677 ^m C.X = 0,377 urn D.X = 0,577 ^m 18S HirOfNG DAN G I A I Cau 1) B Tir m2 = => Ti = T2 => so dao dpng th\rc hi^n cung khoang thai gian t kj nhu Cau 2) B Sau moi chu ki bien dp giam 3% => A ' = 0,97A Tu E' = - k A ' = - k ( , A ) = , - k A ^ =0,94E=:>AE = -0,06E 2 => Phan nSng lugng bj mat sau m6i dao dpng khoang 6% Cau 3) B W = 36.10'^J vaC = )iF K h i u = V: W, = W - W d = W - ^ C u ^ = 27.10"^ J Cau 4) D Bp ph^n may quang iSng kinh, c6 tac dyng phan tach chijm sang phiic t9p nhung phan dan sic la iSng kinh Quang cua anh sang tir bong den 6ng diing gia dinh la quang dam De nh^n biet s\ c6 m$t cua cac nguyen to hoa hpc mau vat, ta phai nghien curu quang v^ch phat xa cua mau Chieu tia laze vao may quang ta thu dugc quang v^ch phat chi c6 v^ch vi tia laze la buc don sac Cau 5) C Khi gifra hai ban ty tren dugc lap day bSng chSt c6 hSng so di?n moi e = thi di?n dung t\ tSng Ian => tan so rieng cua m^ch giam \kn (do ~ ^) Cau 6) B Tia tu ngo^i cung la song difn tir nen la song ngang Cau 7) B Dao dpng cuong buc c6 cpng huong va dao dgng tri cua mpt h^ dao dpng CO chu ki nhu Cau 8) C Suat di?n dpng ciia mpt pin quang di?n chi xuat hi^n pin dugc chieu sang Cau 9) B Chu ki i k dan khong phy thupc khoi luprng nen so chu ki l4c thyrc hi?n dupe khoang thai gian t khong thay doi Cau 10) D Trong thi nghi^m Y- ang ve hi?n tugmg giao thoa vai anh sang dan sSc, vj tri M' tren man quan sat la vj tri van toi hai song anh sang den M ngupc pha Cau 11) D V^t dao dpng dieu hoa, luon c6 gia toe huong ve vj tri can bang 186 Cau 12) B Tinh chat bien d6i nhanh, c h ^ cua pha dugrc d^c tnmg bai chu ki, tan so, t i n so goc a u 13) A Khi di^n ap U R = Uc thi tancp = — ^ = - =>(p = - - : V^y di?n ap giOa hai dau io^n m^ch tre pha so vol i va cos(p = 0,707 Cfiu 14) D H^t nhan c6 dp hyt khoi cang Idm thi ning lugmg lien ket cang Ion Cau 15) C Tir OQ = yjdii 0)2 => o)o = SOTI rad/s Ciiu 16) D Trong 0,25 chu ki dau cua dao dpng di?n tir thi ty phong di?n nen cuomg dp dong qua m^ch tSng Ciiu 17) D Bien dp dao dpng cuong burc phy thupc lye ma sat tac dyng len vat Ciiu 18) B Trong thi nghi^m khao sat dao dpng ciia iSc dcm va lac 16 xo thi gia toe trpng truong g chi anh huong den chu ki ciia \ic 16 xo treo thang dung Cau 19)D Khi tia sang don sSc di tir thuy tinh khong thi mau sSc anh sang khong thay doi tan so khong doi Cau 20) A Khi Ed = 3E, 16 xo khong bien d^mg => Liic li dp v^t c6 dp Ion bang 0,5A T Thai gian 16 xo bj nen chu ki bang — = 0,2 => T = 0,6 s Cau 21) B u = Uo cos((ot + ^) ( V ) ; i - IQ sin((ot + - J ) (A) 571 12 Z, , =>(p = = — =>tan(p = —^ = ^ 12 R => Ti so di?n tra thuan R va cam khang cua cupn cam bang Cau 22) A Trong quang v^ch phat x^ cua hidro, v^ch dupe t^o electron chuyen tu quy d^o M ve quy d^o K la v^ch thupc day Lai-man Cau 23) C Phuong trinh song y = Acos((ot + ) Tir y = 25cos(20t + 5x) cm , x(cm), t(s) => Bien dp dao dpng ciia song la 25 cm + (0 = 20 rad/s n ^ = — = — Hz 2n n 187, + = 5x => X, = 0,47t cm A < = > V = ? t f = cm/s + Song truyen ngirpc chieu duomg ciia tryc Ox => C sai + V^n toe cvrc d^i cua phan tir moi trucmg la coA = 500 cm/s Cau 24) B Di?n ap hai cupn day vuong pha vai di?n ap hai dau mach: z z —z Taco: tancp,d.tan(p = ^ - ^ ^ ^ = - l = > Z^^ + = ZLZC R R Cau 25) C Bien dp dao dpng tong hgp ciia hai dao dpng dieu hoa cung phuomg, cung tan so khong phy thupe vao tan so eua hai dao dgng phan Cau 26) A M^ch RC CO R = 40 n ; (p = - tan(p = - -VJ Ze = 40N/3 Q R Cau 27) A Khi nguyen tur chuyen tir tr^ng thai dung c6 nSng lugng cao sang tr^ng thai dimg CO nang lugng thap thi nguyen tur phat mpt photon la tien de Bo Cau 28) D Tia X va tia tir ngoai tac dyng len cac logi kinh anh khac Cau 29) C Khi may phat di?n xoay chieu pha c6 phan cam quay, phan ung c6 djnh dang ho^t dgng Suat di?n dgng a cupn day c6 gia trj eye tieu ho$c eye d^i cugn day a vj tri each deu hai eye Nam, Bic lien ke Cau 30) B Tan so song f = — = 10 Hz => Song la h^ am nen tai khong nghe dugc K Cau 31) C Trong sy phan h^ch nguai ta khong dimg proton ma dung notron la vi proton mang di^n tich duomg Cau 32>B U = 4kV RP^ Khi H = 10% thi AP = — 2- = 0.1P(l)(Ucoscp) Khi H = 95% thi AP' = — — ^ = 0,05P(2) (U'coscpf L^p ti so (1) vai (2) ^-^^ = 2^\J'^XJyfz => Can tang di^n ap len gip V2 Ian 188 ' Cau 33) C Trong te bao quang di?n, giai h^n quang difn chi phy thupc ban chat kim lo^i dung lam catot Cau 34) D Tu f = 2TCVLC _ c, Khi C = 0,25Ci = ^ thi f: = 2f| Cau ) B Ni = 2200 vong; U, = 220 V; Uj = V U, NT = 60 vong N, Cau ) B Tia gamma khong ciing ban chat vai tia anpha Cau ) A Co nang cua v^t dao dpng dieu hoa chi bang dpng nang ban dau ciia v^t v^t bat dau dao dpng tir vj tri can bang Cau ) D Cau ) B U'ng vai hai giai trj Ri = 20 Q va R2 = 80 ! • ciia bien tror thi cong suit tieu thy do^n m^ch deu bSng 400 W uTif R, + R = — ^ U = 200 V Cau ) C Quang N^ch phat thu dugc chat phat sang a tr^ng thai hay hai nong sang c6 ap suat thap Cau ) A Cau ) C Cau ) D Cau 44) B A = 45° va chiet suat ciia iSng kinh doi vai anh sang mau lyc la n = -Jl => Tia mau lyc di sat m$t ben thur hai ciia lang kinh => chi c6 tia va vang 16 Cau ) B Cau ) D Cau ) D Am may thu ghi nhan dirge c6 tan so Ian han tan so cua am nguon phat may thu chuyen dpng lai gan nguon am dung yen Cau ) A A =eUn eV; Uh -k^ • V = 0,477 ^im Tir 2,2 = — = 0,4 X 189 ^haiiA: Q A P A N cAc vA c]£ HUdiMG D A N E I A I O N LUYEN Q A I H O C VA CAD SANG Dt O N L U Y E N D A I HOC I Phan chung cho tat ca thi sinh (goin 40 cau): Cau 1) Mpt v^t dao dpng dieu hoa vai phuorig trinh x = 5cos(57rt + ) (cm) Sat bao lau ke tir liic t = 0, v^t di dupe quang duong la 42,5 cm ? A.-s B —s C.-s D —s 15 5 Cau 2) Trong s\j phan xa song, neu vat can co djnh thi tai diem phan xa song phan x? va song tai A C O Cling tan so va ciing pha B khac tan so va ngupc pha C CO Cling buac song va ngugc pha D c6 cung toe dp truyen va cung pha Cau 3) Mpt lac dan c6 chieu dai day treo dao dpng dieu hoa vai chu ki T Neu cat bat chieu dai day treo mpt do^n 0,75 m thi chu ki dao dpng bay gia la Ti = s Neu cat tiep day treo di mpt doan 1,25 m nira thi chu ki dao dpng bay gia la = s Chieu dai ciia iSc ban dau va chu ki T ciia no la A l = m ; T = 3V3 s B = m; T = Vs s C I = m ; T = V ^ s D = m; T = ^y3 s Cau 4) Con lac dan (vat n^ng khoi lirpng rn, day treo dai m) dao dpng dieu hoi duai tac dyng cua ngo^i lye F = Focos(27ift )• Lay g = TI^ = 10 m/s"^ Neu tan so f ciia ngo?ii l\rc thay doi tir Hz den Hz thi bien dp dao dpng cua iSc A khong thay doi B tang roi giam C luon tang D luon giam Cau 5)-Treo lac dan vao tran to dang durng yen thi chu ki dao dpng dieu hoa cua lac la 0,500 s Neu cho to chuyen dpng tren duon^ ngang vai gia toe khong doi thi lac khong dao dpng, spi day treo lac l^ch mpt goc » so vai phuong thang dirng Luc neu kich thich l^ii cho lac dao dpng dieuf hoa thi chu ki ciia no xap xi bang A 0,492 s B 0,496 s C 0,507 s D 0,504 s Cau 6) Mpt v^t thyc hi?n dong thai hai dao dpng X | = cos(4nt + (pi) (cm) vai X2= yl3 cos(47rt +— ) (cm) De bien dp dao dpng tong hpp bSng cm thi 91 c6 i gia trj bang A.^ B ^ C.^ D.^ 190 Cau 7) Chpn phat bieu sai: A Bien dp cua dao dpng cuong birc phy thuQC dp chenh l?ch tan so cuong hue va tan so rieng ciia h? dao dpng B Dao dpng tri c6 tan so bang tan so dao dgng rieng cua h? C H i f n tugng cgng hirong ca xay h? dao dpng chju tac dyng cua ngo^i l\rc CO tan so bSng tan so rieng ciia h$ D Dao dpng cua v^t chat long tat dan cang nhanh neu chat long cang it nhot Cau 8) M p t song ca truyen theo phuorng Ox v a i phuong trinh u = 4cos(1007rt - 7tx) (mm) ; x tinh bang met, t tinh bJng giay L i dp ciia diem M each O 50 m vao thai diem t = s la A m m B mm C.-4mm D - mm Cau 9) Phat bieu nao sau day sai noi ve song am? A Dp to ciia am la mpt d$c t n m g sinh l i cua am phy thupc vac tan so am va cuong dp am B Dao dpng phat tCr cac nhgc cy la tong hpp ctia cac hpa am va am ca ban C Song am truyen khong k h i c6 phuang dao dpng vuong goc v o i phuang truyen song D Toe dp truyen am khong nho han toe dp truyen am nuac Cau ) Dai quang lien tyc thu dupe t h i nghi^m ve hi?n tupng tan sac c6 dupe la A thiiy tinh da nhupm mau cho anh sang B l i n g kinh da tach cac mau san c6 anh sang trang cac phan dan sic C anh sang bj nhieu x^ truyen qua iSng kinh D hi^n tupng giao thoa cua cac phan dan sic khoi lang kinh Cau 1 ) Trong hi?n tupmg giao thoa song tren m$t nuac ciia hai nguon ket hgp t?i A va B vai U A = 3cos(1007rt + (PA) (cm); U B = 4cos(1007rt + cpe) (cm) D i e m I nam tren duang trung tryc ciia A B dao dpng v a i bien dp cm N h u vay: A-|(PA-9B=T B |(PA-CPB =n Cau ) M p t khung day dan hinh chCr nh^t quay deu v a i toe dp goc 600 vong/phiit quanh tryc x x ' mpt tir truang deu c6 cac duang cam ung tir vuong goc v a i xx' Suat di?n dpng cam umg khung day bien thien v a i ehu k i bang A 0,1s B 207CS C.2s D s Cau ) Dogn m?ich di?n xoay chieu gom mpt di?n tra thuan va mpt cupn cam thuan mic noi tiep K h i tan so ciia dong d!?n tSng thi di?n ap a hai dau d i f n tra thuan A luon giam B khong doi C luon tang D tang den mpt gia trj eye d^i roi giam 191 C a u 14) Doan mach R L C noi tiep vai cupn day khong tiiuan cam D$t vao hai dau do^n m^ch mpt d i f n ap xoay chieu c6 tan so goc co - thi A dong di^n qua mach cung pha v a i di?n ap hai dau mach B dong d i | n qua m^ch cham pha so v a i di?n ap hai dau mach C dong di?n qua mach nhanh pha han di?n ap hai dau mach D m^ch tieu thy cong suat Ian nhat C a u 15) Doan m^ch di^n gom di^n tra thuan R mSc noi tiep v a i hpp X D^t mpt khoa K vao hai dau cua hpp X Di?n ap giCra hai dau m^ch la u = U >/2 cos(cot + 9) luon on djnh K h i K m a ho$c dong dong difn qua mach deu CO gia trj hi?u dyng la I Di?n tra day noi rat nho, hpp X C O the A gom ty di?n mSc noi tiep v a i cupn day khong thuan cam B chi chura cupn day C gom tvi di?n mac noi tiep cupn thuan cam D chi chura ty di?n C a u 16) Trong phan irng h^t nhan khong c6 djnh lu$t bao toan A so khoi B dpng lixpng C nSng lupng toan phan D dpng nSng K C a u 17) Do^n m^ch di?n R L C noi tiep: cupn cam t h u i n c6 dp t y cam L = — H 71 M p t di?n ap xoay chieu u = 100 > ^ cos(cot + ) ( V ) dupe dat vao hai dau mgch hai dau m^ch Thay doi di^n dung C ciia ty den gia trj Co = 22 nF thi cong suat tieu thy ciia m^ch d^t gia trj eye d^i Tan so cua dong d i f n xap x i bang A 60 Hz B 100 Hz C 50 Hz D 40 Hz C a u 18) M p t may bien ap c6 so vong cupn gap doi so vong cupn N o i hai dau cupn vao di?n ap xoay chieu c6 tan so 50 Hz va gia trj hi?u dyng U = 100 V thi di?n ap a hai dau cupn de c6 tan so va gia trj hi^u dyng \an lupt la A 100 Hz va 200 V B H z v a V C 50-Hz va 200 V D 100 Hz va 100 V C a u 19) D o i v a i may phat di^n xoay chieu pha, A eye bac cua nam cham difn doi di$n v a i cupn day nao thi suat di^n dpng cupn c6 gia trj eye d^i B phan cam la mpt nam ch^m di^n C phan urng hay phan cam deu c6 thk la roto D suat di?n dpng ba cupn day bien thien cung tan so, ciing pha C a u 20) Dpng ca khong dong bp ba pha va may phat di^n xoay chi^u ba pha deu A CO stato gom ba cupn day giong d$t l^ch 120° tren vanh tron B C O roto la nam cham d i f n C ho^t dpng chi dya tren hi?n tupng cam ung di?n tir D CO roto la phan ung 192 Cau 21) Trong truyen thong qua v$ tinh, nguai ta hay dung cac lo^ii song nao sau day? A Song c\rc ngdn B Song ngSn C Song dai D Song trung Cau 22) Chpn phat bieu dung: A Anh sang don sac ichong bj i?ch di qua lang kinh B Hi?n tugng giao thoa, nhieu chung to anh sang c6 tinh chat h^t C Hifn tugng nhilu xay c6 svr g$p ciia hai song anh sang k^t hgrp D Hifn tugng nhieu x?i chumg to anh sang c6 tinh chat song Cau 23) Chpn phat bieu sai: A Dif n truong bien thien theo thai gian se sinh tir truang B Tir truang bien thien theo thai gian se sinh di?n truang c6 cac duang sue la cac duang cong C Di$n truang va tir truang khong the t6n t^i rieng bi?t dpc l^p nhau., D Ta van c6 the chi quan sat dugc ho$c di?n truang ho^c tu truang Cau 24) Ty di^n c6 di^n'dung C = |iF dugc tich di^n den di?n ap cvrc d^i la Uo = V sau mac vai cupn day c6 dif n tra thuan r = Q de t^o m^ch dao dpng Tinh nhi^t lugrng toa ke tu m^ch bat dau dao dpng den liic tat han A.32.10-*J B 16.10"*J C 8.10""*J D lO'^J Cau 25) Chpn phat bieu sai: A Hi?n tugrng t^o cac electron dan va 16 trong ban dan dugc chieu sang dugc gpi la hi^n tugng quang di^n B Hi?n tugng giam m?inh di?n tra suat cua kim lo^i dugc chieu sang thich hgrp gpi la hi?n tugng quang dan C Trong hi^n tugng quang dan, buac song cua anh sang kich thich cang Ion thi dif n tra suat cua ban dan cang nho D Quang di?n tra, pin quang difn la thiet bj ho^t dpng d\ra tren hifn tugmg quang di^n ben Cau 26) Trong sa d6 khoi cua mpt may thu song di?n tu khong c6 bp ph$n nao sau day? A M^ch thu song B M^ch bien di^u C M?ich khuech d^i D Mgch tach song Cau 27) Tia hong ngo^i, tia tu ngogi, tia X, tia gamma deu A CO tinh dam xuyen rat m^nh B lam ion hoa khong C gay hi^n tupng quang di?n ngoai D khong bj l?ch di^n truang va tir truang Cau 28) Theo thu ty khoi lugng nghi tang dan thi c6 bon loai h^t sa cap la A photon, mezon, barion, lepton B photon, lepton, barion, mezon C photon, lepton, mezon, barion D barion, lepton, mezon, photon Cau 29) Trong thi nghi^m Y-ang ve giao thoa anh sang: Khoang each hai khe la mm; khoang each tu hai khe den man la Im; anh sang chieu vao hai khe gom hai dan sac c6 buac song Xi = 0,75 nm va Xi = 0,5 |im Diem M tren man c6 van sang ciing mau van sang trung tam se each van trung tam mpt do^n la A 1,5 mm B mm C 2,5 mm D 1,125 mm 193 C a u 30) M p t chat c6 kha nang phat anh sang c6 birac song = , nm Hdi neu chieu vao birc nao sau day se khong lam cho chat phat quang? A Tiahongngo^i B Tia tir ngo^i C A n h sang t i m D Tia X C a u 31) Chpn phat bieu sai: A Theo thuyet lugng t u thl nang lugng cua mpt chum sang don sac bang so nguyen Ian lugng tur nSng lugng B Nguyen t u , phan t u hap thy anh sang cung c6 nghia la chiing hap thy photon C Cac electron hap thy photon va thoat khoi k i m lo?i deu c6 dp Ion v p toe bang D Song di?n t u c6 buac song cang ngan thi the hi?n tinh hat cang ro C a u 32) Cong thoat ciia electron khoi k i m lo^ii dong, natri, nhorn Ian lupt la; 66,25.10'~°J; 39,75.10'"J va 55,21.1Q-^"J N h u v^y giai h^n quang di?n cua A natri thupc vung hong ngo^ii B dong, nhom thupc vung anh sang nhln thay C d6ng, natri thupc viing anh sang nhin thay D dong, nhom thupc viing tir ngo^i C a u 33) Day A B dai, mpt dau A gin vao am thoa dao dpng v a i tan so f khong thay doi K h i dau B c6 djnh thi tren day hinh song dimg v a i so nut la Biet toe dp truyen song tren day khong doi, neu dau B t y thi tren day A khong the c6 song dimg B c6 song dirng v a i so byng la i C CO song dung v a i so byng la 10 D c6 song dung v a i so nut la C a u 34) Chieu buc gom hai phan dan sac c6 buac song la = 0,3 | i m va Xj = 0,2 | i m vao tarn k i m lo^i (c6 giai h^n quang d i f n XQ = 0,35 |im) Cho h = 6,625.10'^'' Js ; c = 3.10* m/s Dpng nang Ian nhat ma electron thoat khoi k i m lo^i A « 42,59.10"^" J B « 9,46.10-^° J I C « 22,7.10'^" J D 142.10"^° J C a u 35) Mure nang lugng ciia cac tr^ng thai dimg ciia nguyen t u hidro tinh bang cong thirc £„ = eV (n = 1,2, 3, ) K h i khoi hidro bj kich thich, n quang ph6 cua hidro nguai ta chi thu dugc c6 v^ich ph6 H o i tr^ng thai kich thich cao nhat cua cac nguyen tur hidro truong hgp img v a i mure nang lugng la bao nhieu? A.-l,51eV B.-3,4eV C a u 36) Chpn phat bieu diing: C - 0,85 eV D.-2eV \ A Dong vj la nhung nguyen tir ma h^t nhan chura ciing so natron nhung khac sc proton B H^t nhan c6 khoi lugng nghi mo thi c6 nang lugng nghi la E = moc (c = 3.10*m/s) C H^t nhan c6 nang lugng lien ket cang Ian t h i cang ben viing D Lvrc h^t nhan c6 ban kinh tac dyng khoang 10"" m 194 au37) H^t nhan Heli ( j H e ) c6 khoi \\j(?ng 4,0015 u (u = 931,5 M e V / c ^ Biet khoi lugng ciia proton va natron Ian lugt la 1,0073 u va 1,0087 u, nSng lirgng lien ket rieng cua h^t nhan Heli la D MeV A 1,5.10-'*J C.1,5 MeV B.3.ro"j C u 38) D$t mpt di?n ap xoay chieu a u = 100V2cos(l007rt + | ) (V) L,r vao hai dau do^n mach mSc noi tiep »M N B gom bien trcr, ty di?n va cupn day A C di?n trcr ho^t dgng la r = 30 Q O Biet cam khang va dung khang ciia m^ch Ian lugt la lOOQ va Q Thay doi gia trj ciia bien trcr thi cong suat tieu thy cua cupn day d^t eye d^i bang A.40W B 31,25 W C 120 W D 50 W Cau 39) Natri (^^Na) phan vai chu ki T = 2,6 n5m Sau nSm dp phong ciia lixgng Natri nay, c6 khoi lugng ban dau bSng g, se bang A.3,06.10''Bq B 5.10'^Bq C 4,01.10" Bq D 3,9.10''Bq Cau 40) Quang ph6 lien tyc A dung de nh$n biet phan cac chat mau v^t B cac chat hay hai nong sang a ap suat thap phat C khong phy thuQC vao nhi?t dp ciia v^t D cac chat rin, long va cac chat a ap suat Ion bj nung nong phat H Phan rieng: A Tbeo chirong trinh chuan (tir cau 41 den cau 50) Cau 41) Mpt chat diem dao dpng diku hoa vai phuang trinh li dp x = AcoslOOTrt Vao thai diem nao sau day v^t qua vj tri c6 li dp x = cm Ian thu 2009? A.«20,088 s B * 20,086 s C 20 s D 60 s Cau 42) Am Do va am Si mpt cay dan ghi - ta phat khong the cung A dp to B cuang dp am C muc cuang dp am D tan so Cau 43) D^t mpt difn ap xoay chieu u = IOOV2 coslOOTrt (V) vao hai dau do^in m^ich mic noi tiep gom ty di^n va cupn day Di^n ap giCra hai dau cupn day l^ch pha — so vai dong di?n qua m^ch Di^n ap giOa hai dau ty di?n vuong pha vai di?n ap hai dau m^ch Gia trj hi^u dyng cua di^n ap giira hai dau cupn day la A lOOV B.200V C 150V D 50 V 195 Cau 44) Khi hif u di?n the giua Anot va catot cua mgt ong Cu - lit - gia la Ui tl toe dp cua cac electron d^p vao anot la V ) Khi hi?u difn the la U2 thi toe d?' cua cac electron dip vao anot la V2 = 2vi Bo qua dgng nSng ciia cac electron vira b^t khoi catot, khing djnh nao sau day dung? A U , = 2U2,_ B U = 2U, CU, =4U2 D U = 4U, Cau 45) Mpt m l u chat phong c6 khoi lugng m, chu ki ban bSng dem Sau 15 dem khoi lirgrng chat phong \ l ^ i mau la g Khoi lugfng m ban dau la A g B 16g C.24g D.32g Cau 46) Hai dau m^ich di^n RLC noi tiep dugrc mkc vao di?n ap xoay chiSu on djnh Dong difn qua m?ich l^ch pha - j so vai difn ap Neu ta tSng di^n trcr R hai Ian va giO cac thong so khac khong doi thi A h? so cong suat cua m^ch giam B cong suat tieu thy cua m^ch giam C h$ so cong suat cua m^ch khong doi D cong suat tieu thy cua m^ch tSng Cau 47) Kim lo?ii c6 cong thoat cua electron la A Chieu chum anh sang c6 nSn lugrng photon la e > A vao tam kim lo^ii thi A tat ca cac electron thoat khoi kim lo^i voi v^n toe bSng B cac cac electron khong the thoat khoi kim lo^ii C cac electron a be m$t kim lo^i se thoat vai v$n toe 1cm nhlt D cac electron a sau ben kim lo^i sd thoat voi v$n toe Ion nhat Cau 48) ChQn phat bieu sai: A Cho den nay, nguai ta thira nh^n photon la mpt h^t khong the phan chia dugt nira , e 2e B Cac h^t quae va phan quae c6 di?n tich bang ± - , ± — C Thanh cong cua gia thuyet ve h^t quae la da dy doan dirpc sy ton t^i cua h; omega trir D Ngurcri ta da quan sat dupe cac h^t quae ty thi nghi^m Cau 49) Con \kc 16 xo c6 dp cumg K = 100 N/m, dao dpng dieu hoa vai bien d A = cm Lye keo ve tac dyng len v$t t^i vj tri dpng nSng ciia v^t bang Ian tb nang c6 dp Ion la A.2,5N B N C 1,5N D N Cau 50) Trong thi nghi?m Y-ang ve giao thoa anh sang: Khi khe S each deu Si, S thi O la van sang trung tam Djch chuyen khe S theo phuang S1S2 mpt do? y thi t^i O la van toi thur (tinh tir van sang trung tam) Biet khoang each hi khe la a = mm, khoang each tir khe S den m$t phSng chua hai khe Si, S2 la D = 20 cm, buac song ciia anh sang dung thi nghi^m la A, = 0,4 |im y c6 gii tri la A 0,2 mm B mm C mm D 0,5 mm 196 B,Theo chirong trinh nang cao (tir cau 51 den cau 60) Cau 51) Mgt v$t r i n dang quay d^u vai toe dp goc 30 rad/s thi ehju tac dyng cua momen can V$t rin quay ch^m dan deu 10 s roi dirng l ^ i Goc v|it rSn quay dugrc thai gian quay ch^m dan deu la A.350 rad B 200 rad C ISOrad D 50 rad Cau 52) Mpt v$t rSn hit dau quay nhanh dan deu tir tr^ng thai nghi Sau thai gian t v^t d^t toe dp goc la rad/s, liie gia toe huang tarn va gia toe tiep tuy^n eo dp Ian bang Thai gian t bing A 0,5 s B 0,25 s C s D s Cau 53) Chpn phat bieu sai noi ve ehuyen dpng quay cua v$t ran: A Khi tong momen Ivrc tac dyng vao vat bang hang so khae thi vat se quay bien doi deu B Khi tong momen l\rc tac dyng vao v^t bang thi v§t se dung yen ho§c quay deu C Khi v^t quay deu thi mpt diem each tryc quay mpt doan r (r^^O) c6 gia toe goc la hang so khac D Momen quan tinh cua v§t cang Ian thi ta cang kho lam thay d6i tr^ng thai quay cua v|t Cau 54) Mpt AB dong chat vai G la trpng tarn cua thanh, C la mpt diem tren Gpi momen quan tinh ciia doi vai trye quay vuong goc vdi qua G, C Ian lupt la IQ, IC- Bilt = ^ mAB^ (m X , la khoi lupng eiia thanh), de Ic = - 1G thi A.CG=-CB B.CG=-CB C.CG=-CB D.CG = BG Cau 55) Mpt lac 16 xo (v^t njng m = 100 g, 16 xo eo dp cumg k = 100 N/m) treo thang dumg Tir vj tri can bang nang vat len din vj tri 16 xo h'\n mpt do^n X roi buong nh? cho dao dpng dieu hoa Thai gian tir buong v^t den v^t qua vj tri 16 xo khong bien d^ng Ian dau tien la ^ s Cho g = 10 m/s^ -\0 thi bien dp dao dpng ciia v§t la A cm B cm C cm D cm Cau 56) Cho do^n m^ch RLC noi tiep c6 gia trj cac phan tCr c6 djnh D$t vao hai dau do?n mpt di?n ap xoay chieu eo tan so thay doi Khi tan so goc cua d6ng di?n bang (Oo thi cam khang va dung khang c6 gia trj Z L = 100 va Zc = 25 Q De m?ich xay cpng huang, ta phai thay doi tan s6 goc cua d6ng di?n den gia trj CO bang A.2coo B 0,25coo C 4coo D 0,5(0o 197 Cau 57) Mpt dong ho chuyen dpng vai toe dp v = 0,9c Hoi sau 30 phiit (tinh theo dong ho chuyen d^ng) thi dong ho cham hom dong ho di'rng yen bao nhieu phiit? A a 69 phut B « p h u t C * 13 phut D « p h u t Cau 58) Chpn phat bieu sai: A Trong h? M^t Trai, cac hanh tinh deu ty quay quanh no theo cung mpt chiSu B Nhin tong quat, M5t Trai gom hai phan la quang cau va quyen C Cac bien quang c6 6Q sang thay doi theo mpt chu ki xac djnh D Ngirai ta chi phat hi?n 16 den nha tia X phat no hut rngt thien the gan Cau 59) Chieu rngt chum birc c6 birac song A, = 0,1 ^m vao catot cua te bao quang difn Biet cong thoat cua kirn logi lam catot la 2,15 eV Hi?u di?n the giOa Anot va catot la U A K = - V Tinh dpng n§ng cyrc dgi cua cac quang electron den Anot (h = 6,02.10"'^ Js, c = 3.10%/s): A «5,27eV B « 15,27 eV C * " j D « l , e V Cau 60) Chpn phat bieu sai noi ve h^t nhan nguyen tCr c6 nguyen tir so la Z vi so khoi A: A H^it nhan c6 Z proton B So khoi A chinh la so nuclon t^o nen h^it nhan C H^t nhan trung hoa ve di?n D So natron N chinh la hi?u A - Z H I / d N G DAN G I A I Cau 1) A x = 5cos—= t-0:j • t V - -257tsin — < Sau di dupe quang duang S = 42,5 cm = 2.4A + 0,5A v^t den vj tri X = -2,5 cm = -0,5A • T V^y thai gian v^t di dugc quang duang 42,5 cm la t = 2T + — = — s 12 Cau 2) C Cau3)C Chieu dai cua l4c sau cat di 0,75 m la I , = I - 0,75 (m) Chieu dai cua lac sau cat them 1,25 m nOa la I2 = - (m) Tinh I : = T| I2 T^ TinhT: ^ I = - = ^ < ^ 4(1 _ 0,75) = 9(1 - 2) o = m ^ 1, = 2,25 m 4 = - i i > T I, /= 2V3s 198 Acs - Cau 4) D Tan so dao dpng rieng cua lac la fo = 0,5Hz /^^^^ D\fa vao thj, tan so f cua ngo?ii Igc tang tir Hz den Hz thi bien dp giam tit A i den A2 =i>bien dp cua lac luon giam Cau 5) B Khi xe dung yen lac dao dpng v a i gia toe la g O Khi xe chuyen dpng t h i gia toe la g' = Ta CO = - = coslO" cos 10'0 T 0,51 = 2K T ' » 0,496 s Cau 6) B Ta c6: A^ = A,^ + A2^ Hai dao dpng phan vuong pha 371 Cau 7) D Ciiu 8) A M each O l a 50 m = > x = ± m = > u ( ± ; ) = c o s ( 0 t ± r t ) = m m Cau 9) C CaulO)B Cau 1 ) A + Phuong trinh song A truyen tai I : u A, = cos(l OOnt + (py^ 27tAr ) cm X + Phuong trinh song B truyen tai I : U B I =4cos(100jtt + ( p B - ^ ^ ^ ) cm + M a l A = I B , bien dp tong hpp t ^ i I bang cm nen U A I va U B I vuong 7t Cau ) A Tan so goc cua suat di?n dpng khung la co = 20?: rad/s => T = 0,1 s Cau ) A Ta C O di?n ap h i f u dyng giira hai dau di?n tro la U R = IR = U.R Khi t i n so dong di?n tang thi cam khang cua cupn day la Z L tSng R khong doi => i ^ R ^ + Z ^ tang len => U R luon giam 199 ... la: U A = U B = acoscot thi bien dp song tong hgrp t^i M (vai M A = di va MB = d2) la A 2acos7t (di+d2)f B 2asin7: V C 2acos ''d,-d,^ D 2a (di-d2)f COSJt Cau 22 : Trong thi nghifm Y - ang: Gpi... bSng D 1 62 cm va 50 cm C 140 cm va 25 2 cm B 160 cm va 48 cm A 1 42 cm va 25 4 cm Cau 19: Thi nghifm giao thoa khe Y-ang, anh sang c6 birac song X T^i A each Si do?in di va each S2 do^n d2 c6 van... U i c o : ^1- ^2= 1 12 (2) 25 ^1 =81 ^2 (1) T i r ( l ) & ( ) =>K6tqua Cau 19 D T?ii A each Si do^n di va each S2 do^n d2 eo van toi klii d2 - di = (k + — ) X (k = ; ± l ; ± ) Cau 20 C Tan so eua