Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl Câu 1: B Câu 2: C Câu 3: D Câu 4: D Câu 5: B Câu 6: B Câu 7: B Câu 8: B Câu 9: A Câu 10: A Câu 11: A Câu 12: A Câu 13: D Câu 14: D Câu 15: C Câu 16: B Câu 17: C Câu 18: C Câu 19: A Câu 20: A,D Câu 21: A Câu 22: B Câu 23: A Câu 24: D Câu 25: B Câu 26: D Câu 27: D Câu 28: A Câu 29: A Câu 30: D Câu 31: B Câu 32: A Câu 33: C Câu 34: B Câu 35: D Câu 36: B Câu 37: B Câu 38: C Câu 39: B Câu 40: B Câu 41: A Câu 42: D Câu 43: A Câu 44: D Câu 45: C Câu 46: B Câu 47: B Câu 48: D Câu 49: B Câu 50: B Câu 1: D i  Câu 2: L bii gian, li suy ra chn C Câu 3: Mt vu, t s gi  (  thu h 0). Khi t ng gim mt na so v s   A. δ 4 B. δ 16 C. δ 4δ+1 D. δ 3δ+4 Lời giải: [Hinta] 1 1 1 44 4 1 4 4 4 4 4 1 44 34 W W W W . W W WW W . W. W d t d d dd tsau                                   V Câu 5:  bii ta th  vi khoa hai ngn s va chm gia thuyu cp bn s  t t ca thuy truyT truyng A. 7,5m/s. B. 2,5m/s. C. 2,0m/s. D. 4,0m/s. Lời giải : [Hà Dũng] ng kiu 2 vc chiu gc                              V Câu 7: a v  u khic.   Câu 8: Thay thng s thy B sai. Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl Câu 9: Mn t truyn t m n v ng Bc.  mt th m ng t  Bit  ng cm ng t cm ng t  l A. xung; 0,06 T. B.  C.  D. xung; 0,075 T. Lời giải: [Hinta] ng quy tc nm i, suy ra t ng xu  4 0 06 0 15 10 , ( ) , x xT   . V Câu 11: Cho mn t u, hin th cu bn t  0 . Ti thm hiu n th u bn t gin so vi hin th  ch bng kI 0 , vi I 0  i trong m c B. 99,4% A. 99,7% C. 92,3% D. 96,1% Lời giải: [Hà Dũng]                            Hay   V Câu 15: u u = U 2cos(ωt + φ) u mn mch gn tr R mc ni tip vi mt cun cm thun L, bin tr  gp 3 ln ci u R  L lc thi  u n tr  u cun cm thun L  t thm. H th A. 2 2 2 RL 90u +10u = 9U . B. 2 2 2 RL 45u +5u = 9U . C. 2 2 2 RL 5u +45u = 9U . D. 2 2 2 RL 10u +90u = 9U . Lời giải: [Hinta]   22 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 2 2 0 0 0 2 2 2 2 0 0 0 0 2 2 2 3 3 10 99 1 1 9 9 9 9 2 9 10 5 5 45 9 . L R L L R L R L R L L R L R L R L L L RL R Z U U U U u u u u u u U u u U u u U U U U U U U u u U                           Câu 16: Cho phn ng h 2 He 3 + 0 n 1 t ca h 2 He 3 . Bi ht khi cng ngh ct c phn ng nhing ngh ct sau phn  2 = 931 (MeV). A. 7,7187 (MeV). B. 7,7188 (MeV). C. 7,7189 (MeV). D. 7,7186 (MeV). Lời giải : [Hà Dũng] E=3,25=             =>    V Câu 17: Chic x n s f 1 c tc x. Chi hydro bc x n s f 2 c tc x. Bi hydro cho bi biu thc E n = 0 2 E - n (vi E 0 ng s  s tn s ca hai bc x  A. 1 2 f 3 f 10  . B. 1 2 f 10 f3  . C. 1 2 f 25 f 27  . D. 1 2 f 128 f 135  . Lời giải: [Hinta]  3 bc x  c x  n=5  T s tn s hai bc x  2 2 1 1 25 3 1 27 1 5    . V Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl Câu 20: n mch AB gm hai hc ni tip, trong mi hp ch cha mt linh kin thuc lon tr thun, cuc t u n mch AB m 2 cos2ft (V) vi u chnh tn s  f 0 u dng giu h X  Y = 100 3 u t ca m s t cn mn s  tr f 0  A. 12 3 B. 2 1 C. 1 2 D. 3 2 Lời giải: [Hinta]       2 2 2 2 2 2 2 2 2 2 2 2 2 100 3 100 200 2 100 AB Y NhËn xÐt ta thÊy: VËy chøng tá u vu«ng pha víi u . Sau khi t¨ng f th× tÇn sè m¹ch t¨ng, vËy hép Y chÝnh l¯ cuén d©y v¯ hép X l¯ tô ®iÖn YX R L C R L L C C U U U U U U U U U U U U U                  22 3 400 100 3 0 150 50 3 200 3 2 ( ) ( ) v¯ ( ) VËy dÔ d¯ng cã cos L L R C U U v U v U v           Câu 21: m Y- ng thi 2 bc x c m  64,0 1  )  m  48,0 2  n gi    A.  B.  C.  D.  Lời giải: [Hinta]  1 2 0 64 4 0 48 3 , ,    . Suy ra trong khop gi  Vn gi  Câu 22: H 1 1 A Z X   2 2 A Z Y bn. Coi khng hai hng s khi ca  u mu 1 1 A Z X t. Bia 1 1 A Z X  thm t 1  s khng ca 1 1 A Z X  2 2 A Z Y  1 2 A 7A n thm t 2  s kh A. 1 2 7A 8A . B. 1 2 A 31A . C. 1 2 A 32A . D. 1 2 A 14A . Lời giải : [Hà Dũng]                                                  . i   :                                V Câu 24: Chiu bc x n s t kim lo n. Gi s mt p th  dng mt phi bi Nu tn s ca bc x chiu t A. 4K + A B. 2K C. 4K D. 4K + 3A. Lời giải: [Hinta] 43 4 W W W d dsau dsau hf A KA hf A         . V Cõu Lc B Yờu Vt Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl Cõu 26: n mch RLC ni tip, cuthun cm. Khi ni tt t n u dng gin tr n trong hai trung hi nhau. H s sun mng: A. 5 1 . B. 5 2 . C. 10 1 . D. 10 3 . Li gii: [Hinta] c hn d nh H s t: 13 3 10 cos arctank . V Cõu 27: t n u n mch AB ni tip gn tr thun R, t n cm thu t cc. Khi ch L = L 0 u du cun cm U L t c Lmax U . Khi L = L 1 hoc L = L 2 L1 = U L2 = 0,9 Lmax U . H s t ca mch AB khi L = L 1 2 bng 1,44. H s t cn mch AB khi L = L 0 bng A, 0,5 B, 0,6 C, 0,7 D, 0,8 Li gii: [Hinta] 0 10 1 2 0 12 0 9 1 22 1 44 3 max Ta có công thức tính nhanh: U cos Vậy từ bi toán ta có: cos , ( ) Mặt khác 2 giá trị của L cho cùng một U nên ta có công thức: ( ) Bi toán cho ta biết: cos cos , ( ) Từ ( LL L U 2 0 1 10 1 0 0 0 1 0 1 0 1 2 09 0 9 0 8 2 1 44 2 1 44 cos , 1),(2) v (3) ta có: cos , cos , cos .cos , cos cos , V Cỏch khỏc: Li gii ca Admin Kai Shi R ZCosU ZZRR ZRU ZcZR ZU U L CL L L L L )( )( . 2222 =.> R UCos Z U L L =. max2121 2. ) 11 ( L L LL L L L L L Z U ZZ U Z U Z U R CosU Z U CosCos R U L L 0 max max: 21 8.1.8.1 )( 8.0 8.1 21 0 CosCos Cos => ỏp ỏn D Cõu 28: u s dng cho chi c 208 lm/W i nhi nh quang tu nh quang v s tin phi tr cho phn ching dng b s dng ch chii mt kic khong bao nn cho vic chi L gn nht. A. bng. B. ng. C. mt tring. D. ng. Li gii: [Hinta] Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl 100 57 7 120 57 7 62 3 208 120 12 747 6 , , , ., x x k k k k k              Câu 29: n mch xoay chiu AB gm R = 30, cu , L = 0,3 π  n dung C c mc ni tip theo th t n th xoay chiu u = 100 2 cos100i ta thy rng khi C = C m n th hiu dng  n mch cha cu n (U 1 t cc titr ca C m  1min  A. -3 10 3π  B. -3 10 π  C. -3 10 3π  2 V. D. -3 10 π  2 V. Lời giải: [Hinta]         2 2 2 2 2 2 2 2 2 2 1 30 25 2 1 . min min ( ) LC LrC LC LC LrC L C C LrC U r Z Z U U R Rr R r Z Z r Z Z U Z Z Z U Uv R Rr r                  V Câu 30: Cho phn ch ca Urani: 1 235 95 139 1 0 92 42 57 0 27n U Mo La n e       . Bit khng h U = 234,99 u; m Mo = 94,88 u; m La = 138,87 u; m n t to nhit c 6 J/kg. Khi   to  A. 1616 kg B. 1717 kg C. 1818 kg D. 1919 kg Lời giải: [Hà Dũng] E =                  MeV = 3,4473.   1g       =>        ng c     Vy kh      .  Câu 31: Cho mn gm ba phn t mc ni tip theo th t n c t cm n tr thu R = 100   n mu tn s i ta thy khi L = L 1  2 = 1 L 2  th n mch b n tc thi lch pha nhau m ca L 1 n dung C l A. 4 2 3 10 H; F. 33    B. 4 4 3 10 H; F. 33    C. 4 1 3.10 H; F. 4 3    D. 4 4 3 3.10 H; F. 23    Lời giải: [Hinta] Cách giải tổng quát cho mọi bài toán liên quan đế độ lệch pha của dòng điện, có thể hơi dài!!! i, tng tr ng hng nhau. t 21 2   LL Z x Z x  12 2 1,5       C C C Z Z x Z Z x Z x .(1) Khi L=L 1  1 2 tan    C xZ R . Khi L=L 2  2 tan    C Zx R  ng hp l 2 /3   12 2 /3       12 12 12 tan tan tan tan(2 /3) 3 1 tan tan              Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl x (cm) t (10 -1 s) x 1 x 2 22 3. 1 .             C C C C x Z Z x x Z Z x R R R R (2) Kt h 1 400 3 0 5 0 5 0 5 0 5 0 5 3 1 3 200 3 300 3 , , , , , . L C Z x x x x x x R R R R R Z                    V Câu 32: Bn ht  y ra phn ng tt ht ht proton. Bit rng hai hn tn ng 1,21 (MeV). Cho khng c h O m  = 0,21(m O + m p ) 2  p m  = 0,012(m O + m p ) 2 . t   A. 1,555 MeV. B. 1,656 MeV. C. 1,958 MeV. D. 2,559 MeV. Lời giải: [Hà Dũng] ng bng :                                                                =>                          L :                         V Câu 33:  x 1  2  th . Tng t cng   mt th ln nh A.  B.  C.  D.  Lời giải: [Hinta] Ti th ving ca tng v   12 8 2 6 2 2 cos , cosxx            . Vy hai v tng hp bng 10cm/s    200 Max /v A cm s   . Vy  Câu 36: Hai v m c v       ng ca hai v  1 2 8 3cos( )( ) 2 x t cm T    2 2 8cos( )( )x t cm T    . Khong thi gian ngn nht k t khi khoa hai vng nh nhn khi khoa hai vt ln nh K t thu, th vt ci l A. 1,5s. B. 1s. C. 0,5s. D. 0,25s. Lời giải: [Hinta] a hai v 12 8 8 16 23 d x x           Khong thi gian ngn nht k t khi khoa hai vng nh nhn khi kho gia hai vt ln nh Tht ci l 11 1 4 12 . ( )t T s       Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl V Câu 37: a con lu vt  t nh ca con l v  1 n v  2 vi t bi ng ci trung m cn x 1 x 2   v  1 n v  2  A. 1 cm/s. B. 2 cm/s. C. 3 cm/s. D. 4 cm/s. Lời giải: [Hinta]     22 1 2 1 2 1 2 1 2 1 2 1 2 1 2 11 100 100 100 22 1 100 50 100 2 2 2 WW ( / ) tt t k x x t k x x x x t S k x x x x t x x t S t cm s t                        V Câu 38: ng  x 1 = 4cos( +  1 )  x 2 = 4cos( +  2 ) cm. Bit 0   2   1   ng tng hp c x = 4cos( + ) cm. Khi x = - 2  A. x 1 = 0 m. B. x 1 = 2 cm  C. x 2 = 2 cm  D. x 2 =  4 cm. Lời giải: [Hinta] 0   2   1   vy vt 2 s 1 =A 2 =A=4cm. V lch pha gia hai v 0 . Khi x = -  ng tng h -120 0 suy ra v -60 0 . Kt lun: V x 2 = 2 cm . V Câu 39: u con lc ng ch ca tr  0 . Khi con l  0 ng m  ca con l  A. Gim 25%. B.  C D. Gim 50%. Lời giải: [ Hà Dũng] 22 0 00 2 2 2 2 2 0 0 0 0 33 1 2 2 4 4 2 3 2 3 5 2 2 4 2 2 4 4 2 8 Tríc khi chÞu t¸c dông cña ®iÖn trêng: ( ) Khi = th× W qE Khi chÞu t¸c dông ®iÖn trêng: g'=g+ =2g m ' ' ' ( ) Tõ (1) v¯ ( d td mgl mgl WW mg l mgl mgl mgl W W W mgl                       5 1 25 0 25 4 ' 2) , ' , W WWW W         V Câu 40: c gm 7 np lu quãng tám  bit b s do 1 , do 2 T s tn s ca hai nt quãng tám  3 2 () 2 () f do f do  ). Khoa hai nt nhc trong mt quãng tám ng cung nửa cung. Mi quãng tám c chia  gmột cung nửa cung : Hai nt nhnửa cung ng vi hai nt nh s tn s  12 2 (VD: 12 () 2 () f do f si  ). Bit rla 3 n s 440Hz, tn s cdo 1  A. 40 Hz. B. 65 Hz. C. 80 Hz. D. 95 Hz. do rê mi fa sol la si do 1 1 1/2 1 1 1 1/2 Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl Lời giải : [Hà Dũng]        y     n n                      . V Câu 41: Cho mt con lng . Li ci c rng vt gia tc a = g/2 l 1 = 9 N  2 = 5 N. Cho bi  vng h ng ca con l li ci cng A. 10 N. B. 14 N. C. 7 N. D. 4 N. Lời giải : [Gs Xoăn] Câu 42: Cho mt con lng. Mt hc sinh ting. Ln th nht, i th nh i gian ngn nht vn v i trin th t v v  n dng ri th nh i gian ngn nhc phc hi chi s x2 y3  . T s gia tc vc trng ngay khi th ln th nh A. 0,8. B. 1,5. C. 12. D. 2. Lời giải: [Hinta] m t:    m:     m  c tic l n nhau v th  ng h n v ng hp kia.  m 2: Vn v n dang ri th nh t v  kn d  t dao ng t  VTCB suy ra t 2 =T/4 suy ra t 1 =T/6.   1 =T/6. Ti gian v n v n d /3. Khi vt  v n d    .  ng   /cos/3) =    . Gia tc ca vt khi th vt (c ca vt  v   A) Suy ra a = 2g.Hay a/g =. V Câu 43: Ti mn xoay chiu mn th hiu dng  hai cc ci. Ni hai cc ci mt tr s  t t i cung c t ho s k =  n hong ch  n th  pha v n. Do xy ra s c  i ta ni trc tiic ca   Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl A.  B.  C.  D.  Lời giải: [Gs Xoăn] Câu 44: t s ng ti N pha vng ti M. Bi ti b A. 4 cm, 40 cm. B. 4 cm, 60 cm. C. 8 cm, 40 cm. D. 8 cm, 60 cm. Lời giải: [Hinta]  ng tng t t ng hp duy nhnh N. 2 2 20 10 60 66 . ( )MN NP cm          .  2 12 NP    ti N bng 1 n ti bng V Câu 45: Giống i xì đề đại học. Câu 46: Mt ngui, truyu mng. B qua s hp th  ngu  ng A L = 30 dB  B L = 60 dB. i O hai ngun ging ngut ng th n nht ma x L c gần giá trị nào nhất  A. 70 dB. B. 65 dB. C. 77 dB. D. 71 dB. Lời giải : [Hà Dũng]         =30 =>     m cng cao h t O xung             . T c OH=0,9995 OB T c                       V Câu 47: Cho mn AB gm mn tr thun R mc ni tip vi mt t n C vt cu t. Gm ni gin tr thun v m ni gia t n vn mp xoay chi hiu dng 120 3 i, tn s f = 50 Hz u dng gi AN lch pha 2  so v MB ng thi u AB lch pha 3  so vi u AN . Bit ti ca mu ni tu cut ti ca mch bng A. 810 W. B. 540 W. C. 240 W. D. 180 W. Lời giải: [Hinta] Nhc chn cun tr trong r. t chun thy u AN  MB  pha vi u AN . Chn pha ca u AN 0.  Câu Lạc Bộ Yêu Vật Lý _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ https://www.facebook.com/club.yeu.vl   0 26 23 u cos ,u =120 cos ,u =120 cos AN AN MB AB U t t t                     6 2 169 7 3 2 6 120 120 , AB AM MB R MB R AB MB u u u u u u u u                . V n th u mch lch nhau 30 0 . 360 120 3 2 6 cos . .cos ( ) AB P U I I I A         . 60R   . Vt mch khi ni tt cu     2 2 22 120 3 0 540 60 6 .cos cos (W) AB AN R U P R           . V Câu 49: u n n mch AB mc ni ti). Bit t   C , cun cm thu L  2  = 1.  th biu din s ph thui gian ca  gin mn mu dng gim A  A. 50 7 V. B. 25 14 V. C. 25 7 V. D. 12,5 14 V. Lời giải: [Hinta] Nhc c T d ki L , u C  0 L C L C L C Z Z u u u u        L  C  tri AB X uu . T c x i quyt xong   a!!! Ta ving ti thm 2/3 ct l:   2 200 100 3 cos ; cos AN MB u t u t            L   2 200 100 7 3 50 7 2 2 9 AN C X AN MB X MB L X u u u uu u u u u                          7 50 7 50 7 25 14 9 2 () AB X hieudungAB u u U v           . V Hết ng ti hc 2015 ch a. B gng tranh th i gii cho n tham khc vt nhiu thi ng h  Thay mt admin page: Cy  ch   i hc th . A. 2 2 2 RL 90u +10u = 9U . B. 2 2 2 RL 45u +5u = 9U . C. 2 2 2 RL 5u +45u = 9U . D. 2 2 2 RL 10u +90u = 9U . Lời giải: [Hinta]   22 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 2 2 0 0 0 2 2 2 2 0. mn s  tr f 0  A. 12 3 B. 2 1 C. 1 2 D. 3 2 Lời giải: [Hinta]       2 2 2 2 2 2 2 2 2 2 2 2 2 100 3 100 20 0 2 100 AB Y NhËn xÐt ta thÊy: VËy chøng tá. l  A. Gim 25 %. B.  C D. Gim 50%. Lời giải: [ Hà Dũng] 22 0 00 2 2 2 2 2 0 0 0 0 33 1 2 2 4 4 2 3 2 3 5 2 2 4 2 2 4 4 2 8 Tríc khi chÞu t¸c dông