Giai Taco: X = y = ^ T r e n S1S2 b i e n cifc = l , (cm) c6 13 d i e m dao dong vdri dai Ta c6: - < k < CLTC dai gan S2 nhat ' ufng v6i k =, Xet diem M t r e n duofng t r b n S i M = di •- lOcm; SgM = dg T a c6: d i - d2 = 6X = 9cm Suy ra: d2min = 10 - = cm = 10 m.m Vgj' chpn dap an C Cdu 11: H a i dao dong cung phtfotng Ian A, cos 6y (cm) va X2 = 6cos TTt 71 liTgrt c6 phiiorng t r i n h x i = (cm) Dao dong t d n g hcfp cua hai dao dong c6 phiicrng t r i n h x = A cos(jit + cp) (cm) Thay doi Aj cho den k h i b i e n A dat gia t r i 71 A (p = — r a d B ciTc tieu t h i 71 C (p = - — r a d cp = TT r a d D (p = Orad Giai 271 T a c o : A^ = A f f A ; + A , A , c o s ~ - - Af-6A,+36 Suy r a A nho n h a t k h i A i = 3cm (khao sat h a m bac 2) A = 3^/3 c m •cos(p = A,cos~ — = - ^(a^ — A Vdy chpn dap an C Cdu 12: M o t iSc 16 xo dao dong dieu h6a theo phiTcfng ngang vdfi ccf n a n g dao dong la J va ILTC dan h o i CLTC dai la 10 N Moc the n a n g t a i v i t r i can bang Goi Q la dau co d i n h cua 16 xo, khoang t h i gian n g a n n h a t giOfa Ian l i e n tiep Q chiu tac dung liic keo cua 16 xo CO lorn la 0,1 s Quang dudng Idfn n h a t ma vat nho cua 5yf3N iSc d i dtfcfc t r o n g 0,4 s la A 40 cm B 60 cm C 80 cm D 115 cm Giai Ta co: W = - k A ' I J va F = k A = ION A = 20cm 156 Giai Chi ti^t thi T S B H , C D M6n VSt I Khoang thcfi gian ngan n h a t giUa Ian l i e n t i e p Q chiu tac dung lire keo cua 16 xo c6 Idfn sVs N la 0,1s = — => T = 0,6s Sijf dung mo'i quan he cua chuyen dong t r o n deu va dao dong dieu hoa (diTcfng t r o n lu'tfng giac) Chia cac trifong ho'p dac b i e t xac d i n h , S i = 2A = 40cm; tg = 01s quang duong di diidc 16n nhat: t i = 0,3s S2 = 20cm (tCf A A den — hoac ngiTorc lai) 2 • Suy s = 60cm Vay chqn dap an B Cdu 13: Theo mau nguyen tijf Bo, nguyen tuf hidro, chuyen dong cua electron quanh h a t n h a n la chuyen dong t r o n deu T i so giOfa toe cua electron t r e n quy dao K va toe cua electron t r e n quy dao M bSng A B A p dung cong thufc: C k q.q2 k qiq, D Giai mv" r v„" fw 9r„ ^ v Vdy chgn dap an C Cdu 14: K h i n o i ve t i n h chat cua t i a tuf ngoai, p h a t bieu nao sau day la s a i ? A T i a tuf ngoai l a m i o n hoa k h o n g k h i B Tia tuf ngoai k i c h t h i c h sii p h a t quf.ng cua n h i e u chat C Tia tuf ngoai tac dung len p h i m a n h D Tia tuf ngoai k h o n g hi n\i6c hap t h u Giai Chgn dap an D Cdu 15: T r o n g m o t p h a n ufng h a t nhai^, c6 sir bao t o a n A so p r o t o n B so nuclon C so nottron D k h o i li/gfng Giai Chon dap an B Cdu 16: T a i d i e m O t r o n g m o i trUcfng d^ng hiidng, khong hap thu am, CO nguon a m diem, giong vdfi cong suat p h a t a m k h o n g doi Tai diem A c6 mufc ciTo'ng a m 20 dB De t a i t r u n g d i e m M cua doan Giai Chi tiet de thi T S DH C D Mon Vat li 57 OA CO mufc CLTofng a m la 30 dB t h i so nguon a m giong cac nguon a m t r e n can d a t t h e m t a i O bang A B C D Giai Taco: - = I (OA l O l g - ^ = lOlg L M = 26dB Goi cong suat cua m i nguon la P, t a c6: p —; 47iR- =— I L = 101g-=> L I'M M _ nP 2P 10 10 n 10^ 10 2,6 = 2,5=>n = Can d a t t h e m nguon Vay chon dap an B Cdu 17: H a t n h a n u r a n i sau m o t chuoi phan r a , bien doi t h a n h h a t n h a n chi '^''jPh T r o n g qua t r i n h do, chu k i b a n r a cua 'HU bien doi t h a n h h a t n h a n chi la 4,47.10^ n a m M o t k h o i da dUcfc phat hien c6 chiifa 1,188.10^° h a t n h a n " ^ U va 6,239.10^^ h a t n h a n 'l'?h Gia suf k h o i da luc mdfi h i n h t h a n h k h o n g chufa chi va t a t ca liicJng chi c6 mat t r o n g deu l a san pham*phan r a cua Tuoi ciia k h o i da k h i dugc p h a t h i e n la D 2,5.10*^ n a m C 3,5.10^ n a m B 6,3.10^ n a m A 3,3.10^ n a m Giai Ta c6: N = 1,188.10^" h a t n h a n No = 1,188.10^° + 6,239.10'^ = 1,25039.10^° h a t n h a n t = T- N 4,47.1 In o'>.Mlll = 0.33.10" = 3,3.10« 0693 nam Vay chgn dap an A Cdu 18: T r o n g t h i nghiem Y-ang ve giao thoa a n h sang, nguon sang phat dong tho'i hai anh sang do'n sic Xi, X2 c6 biio'c song Ian lu'cft la 0,48).im va 0,60fim T r e n m a n quan sat, khoang giufa hai v a n sang gan n h a t v a cung m a u vdfi v a n sang t r u n g tarn c6 A v a n sang A,i va v a n sang X2 B v a n sang Xi va v a n sang A,2 C v a n sang A I va v a n sang X2D v a n sang Xi va v a n sang A.2 Giai chi tiet de thi T S D H , C D Mon Vat li 58 ... c6 A v a n sang A,i va v a n sang X2 B v a n sang Xi va v a n sang A ,2 C v a n sang A I va v a n sang X2D v a n sang Xi va v a n sang A .2 Giai chi tiet de thi T S D H , C D Mon Vat li 58 ... Taco: - = I (OA l O l g - ^ = lOlg L M = 26 dB Goi cong suat cua m i nguon la P, t a c6: p —; 47iR- =— I L = 101g-=> L I'M M _ nP 2P 10 10 n 10^ 10 2, 6 = 2, 5=>n = Can d a t t h e m nguon Vay chon... trifong ho'p dac b i e t xac d i n h , S i = 2A = 40cm; tg = 01s quang duong di diidc 16n nhat: t i = 0,3s S2 = 20 cm (tCf A A den — hoac ngiTorc lai) 2 • Suy s = 60cm Vay chqn dap an B Cdu 13: