C\u00e2u<\/strong> 3: M\u1ea1ch dao \u0111\u1ed9ng \u0111i\u1ec7n t\u1eeb LC g\u1ed3m m\u1ed9t cu\u1ed9n d\u00e2y c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m 50 mH v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung 5 mF. N\u1ebfu m\u1ea1ch c\u00f3 \u0111i\u1ec7n tr\u1edf thu\u1ea7n 10^{-2<\/sup> W, \u0111\u1ec3 duy tr\u00ec dao \u0111\u1ed9ng trong m\u1ea1ch v\u1edbi hi\u1ec7u \u0111i\u1ec7n th\u1ebf c\u1ef1c \u0111\u1ea1i gi\u1eefa hai b\u1ea3n t\u1ee5 \u0111i\u1ec7n l\u00e0 12 V th\u00ec ph\u1ea3i cung c\u1ea5p cho m\u1ea1ch \u0111i\u1ec7n n\u0103ng trong 1 ph\u00fat b\u1eb1ng<\/p>\n}

A. 36mJ \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 B.4,32J \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0C. 4,32mJ\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C.72 MJ<\/p>\n

C\u00e2u<\/strong> 4: M\u1ed9t ch\u1ea5t \u0111i\u1ec3m dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a tr\u00ean tr\u1ee5c Ox v\u1edbi qu\u1ef9 \u0111\u1ea1o d\u00e0i\u00a0 20 cm, t\u1ea7n s\u1ed1 0,5Hz. M\u1ed1c th\u1ebf n\u0103ng \u1edf v\u1ecb tr\u00ed c\u00e2n b\u1eb1ng. T\u1ed1c \u0111\u1ed9 trung b\u00ecnh c\u1ee7a ch\u1ea5t \u0111i\u1ec3m trong kho\u1ea3ng th\u1eddi gian ng\u1eafn nh\u1ea5t khi ch\u1ea5t \u0111i\u1ec3m \u0111i t\u1eeb v\u1ecb tr\u00ed c\u00f3 \u0111\u1ed9ng n\u0103ng b\u1eb1ng 3 l\u1ea7n th\u1ebf n\u0103ng \u0111\u1ebfn v\u1ecb tr\u00ed c\u00f3 \u0111\u1ed9ng n\u0103ng b\u1eb1ng 1\/3 l\u1ea7n th\u1ebf n\u0103ng l\u00e0?<\/p>\n

\n
1. 14,64cm\/s B.21,96cm\/s C.26,12cm\/s\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 D.7,32cm\/s<\/li>\n<\/ol>\n

   C\u00e2u<\/strong> 5: Khi n\u00f3i v\u1ec1 m\u1ed9t v\u1eadt dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a, ph\u00e1t bi\u1ec3u n\u00e0o sau \u0111\u00e2y sai<\/strong>?<\/p>\n\n\n\n\n\n\n

   A.<\/strong><\/td>\n	C\u01a1 n\u0103ng c\u1ee7a v\u1eadt bi\u1ebfn thi\u00ean tu\u1ea7n ho\u00e0n theo th\u1eddi gian.<\/td>\n<\/tr>\n
   B.<\/strong><\/td>\n	V\u1eadn t\u1ed1c c\u1ee7a v\u1eadt bi\u1ebfn thi\u00ean \u0111i\u1ec1u h\u00f2a theo th\u1eddi gian<\/td>\n<\/tr>\n
   C.<\/strong><\/td>\n	\u0110\u1ed9ng n\u0103ng c\u1ee7a v\u1eadt bi\u1ebfn thi\u00ean tu\u1ea7n ho\u00e0n theo th\u1eddi gian.<\/td>\n<\/tr>\n
   D.<\/strong><\/td>\n	L\u1ef1c k\u00e9o v\u1ec1 t\u00e1c d\u1ee5ng l\u00ean v\u1eadt bi\u1ebfn thi\u00ean \u0111i\u1ec1u h\u00f2a theo th\u1eddi gian.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n C\u00e2u<\/strong> 6: Trong m\u1ea1ch dao \u0111\u1ed9ng LC l\u00ed t\u01b0\u1edfng \u0111ang c\u00f3 dao \u0111\u1ed9ng \u0111i\u1ec7n t\u1eeb t\u1ef1 do. Th\u1eddi gian ng\u1eafn nh\u1ea5t \u0111\u1ec3 n\u0103ng l\u01b0\u1ee3ng \u0111i\u1ec7n tr\u01b0\u1eddng gi\u1ea3m t\u1eeb gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i xu\u1ed1ng c\u00f2n m\u1ed9t n\u1eeda gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i l\u00e0 1,5.10-4<\/sup>s. Th\u1eddi gian ng\u1eafn nh\u1ea5t \u0111\u1ec3 \u0111i\u1ec7n t\u00edch tr\u00ean t\u1ee5 gi\u1ea3m t\u1eeb gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i xu\u1ed1ng c\u00f2n m\u1ed9t n\u1eeda gi\u00e1 tr\u1ecb \u0111\u00f3 l\u00e0<\/p>\n\n\n\n A.<\/strong><\/td>\n 3.10-4<\/sup>s.<\/td>\n B.<\/strong><\/td>\n 12.10-4<\/sup>s.<\/td>\n C.<\/strong><\/td>\n 2.10-4<\/sup>s.<\/td>\n D.<\/strong><\/td>\n 6.10-4<\/sup>s.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n <\/p>\n C\u00e2u<\/strong> 8: Th\u1ef1c hi\u1ec7n th\u00ed nghi\u1ec7m Y-\u00e2ng v\u1ec1 giao thoa v\u1edbi \u00e1nh s\u00e1ng \u0111\u01a1n s\u1eafc m\u00e0u lam ta quan s\u00e1t \u0111\u01b0\u1ee3c h\u1ec7 v\u00e2n giao thoa tr\u00ean m\u00e0n. N\u1ebfu thay \u00e1nh s\u00e1ng \u0111\u01a1n s\u1eafc m\u00e0u lam b\u1eb1ng \u00e1nh s\u00e1ng \u0111\u01a1n s\u1eafc m\u00e0u v\u00e0ng v\u00e0 c\u00e1c \u0111i\u1ec1u ki\u1ec7n kh\u00e1c c\u1ee7a th\u00ed nghi\u1ec7m \u0111\u01b0\u1ee3c gi\u1eef nguy\u00ean th\u00ec<\/p>\n\n\n\n\n A.<\/strong><\/td>\n kho\u1ea3ng v\u00e2n kh\u00f4ng thay \u0111\u1ed5i.<\/td>\n B.<\/strong><\/td>\n v\u1ecb tr\u00ed v\u00e2n trung t\u00e2m thay \u0111\u1ed5i.<\/td>\n<\/tr>\n C.<\/strong><\/td>\n kho\u1ea3ng v\u00e2n t\u0103ng l\u00ean.<\/td>\n D.<\/strong><\/td>\n kho\u1ea3ng v\u00e2n gi\u1ea3m xu\u1ed1ng.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n <\/a><\/p>\n C\u00e2u<\/strong> 11: M\u1ed9t s\u00f3ng h\u00ecnh sin truy\u1ec1n theo ph\u01b0\u01a1ng Ox t\u1eeb ngu\u1ed3n O v\u1edbi t\u1ea7n s\u1ed1 20 Hz, c\u00f3 t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng n\u1eb1m trong kho\u1ea3ng t\u1eeb 70 cm\/s \u0111\u1ebfn 100 cm\/s. G\u1ecdi A v\u00e0 B l\u00e0 hai \u0111i\u1ec3m n\u1eb1m tr\u00ean Ox, \u1edf c\u00f9ng m\u1ed9t ph\u00eda so v\u1edbi O v\u00e0 c\u00e1ch nhau 10 cm. Hai ph\u1ea7n t\u1eed m\u00f4i tr\u01b0\u1eddng t\u1ea1i A v\u00e0 B lu\u00f4n dao \u0111\u1ed9ng ng\u01b0\u1ee3c pha v\u1edbi nhau. B\u01b0\u1edbc s\u00f3ng l\u00e0<\/p>\n\n\n\n A.<\/strong><\/td>\n 20 cm<\/td>\n B.<\/strong><\/td>\n 9cm<\/td>\n C.<\/strong><\/td>\n 10cm<\/td>\n D.<\/strong><\/td>\n 8cm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n <\/a><\/p>\n C\u00e2u<\/strong> 13: Trong dao \u0111\u1ed9ng \u0111i\u1ec7n t\u1eeb chu k\u1ef3 T <\/em>c\u1ee7a m\u1ea1ch LC. N\u0103ng l\u01b0\u1ee3ng \u0111i\u1ec7n t\u1eeb tr\u01b0\u1eddng<\/p>\n\n\n\n\n A.<\/strong><\/td>\n bi\u1ebfn thi\u00ean v\u1edbi chu k\u00ec b\u1eb1ng T<\/em><\/td>\n B.<\/strong><\/td>\n kh\u00f4ng \u0111\u1ed5i<\/td>\n<\/tr>\n C.<\/strong><\/td>\n bi\u1ebfn thi\u00ean v\u1edbi chu k\u00ec b\u1eb1ng T<\/em>\/2<\/td>\n D.<\/strong><\/td>\n bi\u1ebfn thi\u00ean v\u1edbi chu k\u00ec b\u1eb1ng 2T<\/em><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n C\u00e2u<\/strong> 14: Kho\u1ea3ng c\u00e1ch t\u1eeb hai khe Young \u0111\u1ebfn m\u00e0n E l\u00e0 2m, ngu\u1ed3n s\u00e1ng S c\u00e1ch \u0111\u1ec1u hai khe v\u00e0 c\u00e1ch m\u1eb7t ph\u1eb3ng ch\u1ee9a hai khe l\u00e0 0,5m. N\u1ebfu ngu\u1ed3n s\u00e1ng S v\u00e0 m\u00e0n E c\u1ed1 \u0111\u1ecbnh, d\u1eddi hai khe theo ph\u01b0\u01a1ng song song v\u1edbi m\u00e0n E m\u1ed9t \u0111o\u1ea1n 2mm v\u1ec1 ph\u00eda tr\u00ean th\u00ec h\u1ec7 v\u00e2n tr\u00ean m\u00e0n E s\u1ebd di chuy\u1ec3n nh\u01b0 th\u1ebf n\u00e0o?<\/p>\n\n\n\n\n A.<\/strong><\/td>\n D\u1eddi v\u1ec1 ph\u00eda d\u01b0\u1edbi m\u1ed9t \u0111o\u1ea1n 10mm<\/td>\n B.<\/strong><\/td>\n D\u1eddi v\u1ec1 ph\u00eda tr\u00ean m\u1ed9t \u0111o\u1ea1n m<\/td>\n<\/tr>\n C.<\/strong><\/td>\n D\u1eddi v\u1ec1 ph\u00eda d\u01b0\u1edbi m\u1ed9t \u0111o\u1ea1n m<\/td>\n D.<\/strong><\/td>\n D\u1eddi v\u1ec1 ph\u00eda tr\u00ean m\u1ed9t \u0111o\u1ea1n 10mm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n <\/a><\/strong><\/p>\n C\u00e2u 16: Ph\u00e1t bi\u1ec3u n\u00e0o sau \u0111\u00e2y l\u00e0 \u0111\u00fang khi n\u00f3i v\u1ec1 s\u00f3ng c\u01a1?<\/p>\n A. B\u01b0\u1edbc s\u00f3ng l\u00e0 kho\u1ea3ng c\u00e1ch gi\u1eefa hai \u0111i\u1ec3m tr\u00ean c\u00f9ng m\u1ed9t ph\u01b0\u01a1ng truy\u1ec1n s\u00f3ng m\u00e0 dao \u0111\u1ed9ng t\u1ea1i hai \u0111i\u1ec3m \u0111\u00f3 c\u00f9ng pha<\/p>\n B. S\u00f3ng c\u01a1 truy\u1ec1n trong ch\u1ea5t r\u1eafn lu\u00f4n l\u00e0 s\u00f3ng d\u1ecdc<\/p>\n C. S\u00f3ng c\u01a1 truy\u1ec1n trong ch\u1ea5t l\u1ecfng lu\u00f4n l\u00e0 s\u00f3ng ngang<\/p>\n D.B\u01b0\u1edbc s\u00f3ng l\u00e0 kho\u1ea3ng c\u00e1ch gi\u1eefa hai \u0111i\u1ec3m g\u1ea7n nhau nh\u1ea5t tr\u00ean c\u00f9ng m\u1ed9t ph\u01b0\u01a1ng truy\u1ec1n s\u00f3ng m\u00e0 dao \u0111\u1ed9ng t\u1ea1i hai \u0111i\u1ec3m \u0111\u00f3 c\u00f9ng pha<\/p>\n C\u00e2u 17: Trong m\u1ed9t m\u00e1y ph\u00e1t \u0111i\u1ec7n 3 pha, khi su\u1ea5t \u0111i\u1ec7n \u0111\u1ed9ng \u1edf m\u1ed9t pha \u0111\u1ea1t gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i e1<\/sub> = Eo<\/sub> th\u00ec c\u00e1c su\u1ea5t \u0111i\u1ec7n \u0111\u1ed9ng kia \u0111\u1ea1t gi\u00e1 tr\u1ecb<\/p>\n\n\n\n\n A.<\/td>\n e2<\/sub> = \u2013 0,866Eo, e3<\/sub> = \u2013 0,866Eo<\/td>\n B.<\/td>\n e2<\/sub> = -Eo\/2, e3<\/sub> = Eo\/2<\/td>\n<\/tr>\n C.<\/td>\n e2<\/sub> = Eo\/2, e3<\/sub> = Eo\/2<\/td>\n D.<\/td>\n e2<\/sub> = -Eo\/2, e3<\/sub> = -Eo\/2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n C\u00e2u 18: \u0110\u1ec3 kh\u1ea3o s\u00e1t giao thoa s\u00f3ng c\u01a1, ng\u01b0\u1eddi ta b\u1ed1 tr\u00ed tr\u00ean m\u1eb7t n\u01b0\u1edbc n\u1eb1m ngang hai ngu\u1ed3n k\u1ebft h\u1ee3p S1<\/sub> v\u00e0 S2<\/sub>. Hai ngu\u1ed3n n\u00e0y dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a theo ph\u01b0\u01a1ng th\u1eb3ng \u0111\u1ee9ng, c\u00f9ng pha. Xem bi\u00ean \u0111\u1ed9 s\u00f3ng kh\u00f4ng thay \u0111\u1ed5i trong qu\u00e1 tr\u00ecnh truy\u1ec1n s\u00f3ng. C\u00e1c \u0111i\u1ec3m thu\u1ed9c m\u1eb7t n\u01b0\u1edbc v\u00e0 n\u1eb1m tr\u00ean \u0111\u01b0\u1eddng trung tr\u1ef1c c\u1ee7a \u0111o\u1ea1n S1<\/sub>S2<\/sub> s\u1ebd:<\/p>\n\n\n\n\n A.<\/td>\n kh\u00f4ng dao \u0111\u1ed9ng<\/td>\n B.<\/td>\n dao \u0111\u1ed9ng v\u1edbi bi\u00ean \u0111\u1ed9 b\u1eb1ng n\u1eeda bi\u00ean \u0111\u1ed9 c\u1ef1c \u0111\u1ea1i<\/td>\n<\/tr>\n C.<\/td>\n dao \u0111\u1ed9ng v\u1edbi bi\u00ean \u0111\u1ed9 c\u1ef1c \u0111\u1ea1i<\/td>\n D.<\/td>\n dao \u0111\u1ed9ng v\u1edbi bi\u00ean \u0111\u1ed9 c\u1ef1c ti\u1ec3u<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n <\/a><\/p>\n <\/a><\/p>\n C\u00e2u 22: Trong m\u1ed9t m\u00f4i tr\u01b0\u1eddng v\u1eadt ch\u1ea5t \u0111\u00e0n h\u1ed3i c\u00f3 hai ngu\u1ed3n k\u1ebft h\u1ee3p A v\u00e0 B c\u00e1ch nhau 10 cm, c\u00f9ng t\u1ea7n s\u1ed1. Khi \u0111\u00f3 t\u1ea1i v\u00f9ng gi\u1eefa hai ngu\u1ed3n ng\u01b0\u1eddi ta quan s\u00e1t th\u1ea5y xu\u1ea5t hi\u1ec7n 10 d\u00e3y dao \u0111\u1ed9ng c\u1ef1c \u0111\u1ea1i v\u00e0 c\u1eaft \u0111o\u1ea1n S\u00ad1<\/sub>S2<\/sub> th\u00e0nh 11 \u0111o\u1ea1n m\u00e0 hai \u0111o\u1ea1n g\u1ea7n c\u00e1c ngu\u1ed3n ch\u1ec9 d\u00e0i b\u1eb1ng m\u1ed9t n\u1eeda c\u00e1c \u0111o\u1ea1n c\u00f2n l\u1ea1i. Bi\u1ebft T\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng trong m\u00f4i tr\u01b0\u1eddng \u0111\u00f3 l\u00e0 50 (cm\/s). T\u00ednh t\u1ea7n s\u1ed1:<\/p>\n\n\n\n A<\/td>\n 25 Hz<\/td>\n B.<\/td>\n 30 Hz<\/td>\n C.<\/td>\n 35 Hz<\/td>\n D.<\/td>\n 40 Hz<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n C\u00e2u 23: Dao \u0111\u1ed9ng c\u1ee7a m\u1ed9t ch\u1ea5t \u0111i\u1ec3m c\u00f3 kh\u1ed1i l\u01b0\u1ee3ng 100 g l\u00e0 t\u1ed5ng h\u1ee3p c\u1ee7a hai dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a c\u00f9ng ph\u01b0\u01a1ng, c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh li \u0111\u1ed9 l\u1ea7n l\u01b0\u1ee3t l\u00e0 x1<\/sub> = 5cos10t v\u00e0 x2<\/sub> = 20cos(10t+\u03c0) (x1<\/sub> v\u00e0 x2<\/sub> t\u00ednh b\u1eb1ng cm, t t\u00ednh b\u1eb1ng s). M\u1ed1c th\u1ebf n\u0103ng \u1edf v\u1ecb tr\u00ed c\u00e2n b\u1eb1ng. C\u01a1 n\u0103ng c\u1ee7a ch\u1ea5t \u0111i\u1ec3m b\u1eb1ng<\/p>\n\n\n\n A<\/td>\n 0,1125 J.<\/td>\n B.<\/td>\n 0,225 J.<\/td>\n C.<\/td>\n 112,5 J.<\/td>\n D.<\/td>\n 225 J.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Nh\u1eefng\u00a0 c\u00e2u tr\u1eafc nghi\u1ec7m c\u00f2n l\u1ea1i trong 50 c\u00e2u tr\u1eafc nghi\u1ec7m \u0111\u1ec1 thi th\u1eed m\u00f4n v\u1eadt l\u00fd 2017<\/strong><\/p>\n <\/a><\/p>\n C\u00e2u 26: Tia R\u01a1n-ghen (tia X) c\u00f3<\/p>\n\n\n\n\n A.<\/td>\n c\u00f9ng b\u1ea3n ch\u1ea5t v\u1edbi tia t\u1eed ngo\u1ea1i.<\/td>\n B.<\/td>\n t\u1ea7n s\u1ed1 nh\u1ecf h\u01a1n t\u1ea7n s\u1ed1 c\u1ee7a tia h\u1ed3ng ngo\u1ea1i.<\/td>\n<\/tr>\n C.<\/td>\n c\u00f9ng b\u1ea3n ch\u1ea5t v\u1edbi s\u00f3ng \u00e2m.<\/td>\n D.<\/td>\n \u0111i\u1ec7n t\u00edch \u00e2m n\u00ean n\u00f3 b\u1ecb l\u1ec7ch trong \u0111i\u1ec7n tr\u01b0\u1eddng v\u00e0 t\u1eeb tr\u01b0\u1eddng.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n C\u00e2u 27: Chi\u1ebfu t\u1eeb n\u01b0\u1edbc ra kh\u00f4ng kh\u00ed m\u1ed9t ch\u00f9m tia s\u00e1ng song song r\u1ea5t h\u1eb9p (coi nh\u01b0 m\u1ed9t tia s\u00e1ng) g\u1ed3m 5 th\u00e0nh ph\u1ea7n \u0111\u01a1n s\u1eafc: t\u00edm, lam, \u0111\u1ecf, l\u1ee5c, v\u00e0ng. Tia l\u00f3 \u0111\u01a1n s\u1eafc m\u00e0u l\u1ee5c \u0111i l\u00e0 l\u00e0 m\u1eb7t n\u01b0\u1edbc (s\u00e1t v\u1edbi m\u1eb7t ph\u00e2n c\u00e1ch gi\u1eefa hai m\u00f4i tr\u01b0\u1eddng). Kh\u00f4ng k\u1ec3 tia \u0111\u01a1n s\u1eafc m\u00e0u l\u1ee5c, c\u00e1c tia l\u00f3 ra ngo\u00e0i kh\u00f4ng kh\u00ed l\u00e0 c\u00e1c tia \u0111\u01a1n s\u1eafc m\u00e0u:<\/p>\n\n\n\n A<\/td>\n \u0111\u1ecf, v\u00e0ng.<\/td>\n B.<\/td>\n lam, t\u00edm.<\/td>\n C.<\/td>\n \u0111\u1ecf, v\u00e0ng, lam.<\/td>\n D.<\/td>\n t\u00edm, lam, \u0111\u1ecf.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n <\/a><\/p>\n <\/a><\/p>\n <\/a><\/p>\n C\u00e2u 35: M\u1ed9t m\u00e1y bi\u1ebfn \u00e1p , cu\u1ed9n s\u01a1 c\u1ea5p c\u00f3 500 v\u00f2ng d\u00e2y, cu\u1ed9n th\u1ee9 c\u1ea5p c\u00f3 50 v\u00f2ng d\u00e2y. \u0110i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng \u1edf hai \u0111\u1ea7u cu\u1ed9n s\u01a1 c\u1ea5p l\u00e0 100V. Bi\u1ebft ch\u1ec9 70% \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb do cu\u1ed9n s\u01a1 c\u1ea5p \u0111i v\u00e0o cu\u1ed9n th\u1ee9 c\u1ea5p. \u0111i\u1ec7n \u00e1p \u1edf cu\u1ed9n th\u1ee9 c\u1ea5p l\u00e0:<\/p>\n\n\n\n A<\/td>\n 7V<\/td>\n B.<\/td>\n 1000V<\/td>\n C.<\/td>\n 10V<\/td>\n D.<\/td>\n 700V<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n C\u00e2u 36: Ph\u00e1t bi\u1ec3u n\u00e0o sau \u0111\u00e2y l\u00e0 sai khi n\u00f3i v\u1ec1 s\u00f3ng \u0111i\u1ec7n t\u1eeb?<\/p>\n\n\n\n\n\n\n A.<\/td>\n Khi s\u00f3ng \u0111i\u1ec7n t\u1eeb g\u1eb7p m\u1eb7t ph\u00e2n c\u00e1ch gi\u1eefa hai m\u00f4i tr\u01b0\u1eddng th\u00ec n\u00f3 c\u00f3 th\u1ec3 b\u1ecb ph\u1ea3n x\u1ea1 v\u00e0 kh\u00fac x\u1ea1.<\/td>\n<\/tr>\n B.<\/td>\n S\u00f3ng \u0111i\u1ec7n t\u1eeb l\u00e0 s\u00f3ng ngang n\u00ean n\u00f3 ch\u1ec9 truy\u1ec1n \u0111\u01b0\u1ee3c trong ch\u1ea5t r\u1eafn.<\/td>\n<\/tr>\n C.<\/td>\n Trong s\u00f3ng \u0111i\u1ec7n t\u1eeb th\u00ec dao \u0111\u1ed9ng c\u1ee7a \u0111i\u1ec7n tr\u01b0\u1eddng v\u00e0 c\u1ee7a t\u1eeb tr\u01b0\u1eddng t\u1ea1i m\u1ed9t \u0111i\u1ec3m lu\u00f4n \u0111\u1ed3ng pha v\u1edbi nhau.<\/td>\n<\/tr>\n D.<\/td>\n S\u00f3ng \u0111i\u1ec7n t\u1eeb truy\u1ec1n \u0111\u01b0\u1ee3c trong ch\u00e2n kh\u00f4ng.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n  <\/p>\n <\/a><\/p>\n <\/a><\/p>\n C\u00e2u 42: Cho m\u1ea1ch m\u1ed9t cu\u1ed9n c\u1ea3m m\u1eafc n\u1ed1i ti\u1ebfp v\u1edbi m\u1ed9t t\u1ee5 \u0111i\u1ec7n C1<\/sub> th\u00ec m\u1ea1ch thu \u0111\u01b0\u1ee3c s\u00f3ng \u0111i\u1ec7n t\u1eeb c\u00f3 b\u01b0\u1edbc s\u00f3ng l1<\/sub>, thay t\u1ee5 tr\u00ean b\u1eb1ng t\u1ee5 C2<\/sub> th\u00ec m\u1ea1ch thu \u0111\u01b0\u1ee3c s\u00f3ng \u0111i\u1ec7n t\u1eeb c\u00f3 l2<\/sub>. H\u1ecfi m\u1eafc \u0111\u1ed3ng th\u1eddi hai t\u1ee5 song song v\u1edbi nhau r\u1ed3i m\u1eafc v\u00e0o cu\u1ed9n c\u1ea3m th\u00ec m\u1ea1ch thu \u0111\u01b0\u1ee3c s\u00f3ng c\u00f3 b\u01b0\u1edbc s\u00f3ng l\u00e0 bao nhi\u00eau?<\/p>\n\n\n\n A<\/td>\n l = (l1<\/sub> + l2<\/sub>)1\/2<\/sup><\/td>\n B.<\/td>\n l2<\/sup> = l2<\/sup>1<\/sub> + l2<\/sub>2<\/sup><\/td>\n C.<\/td>\n \u00a0(l1<\/sub> + l2<\/sub>)<\/td>\n D.<\/td>\n l = (l1<\/sub>. l2<\/sub>)1\/2<\/sup><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n C\u00e2u 43: M\u1ed9t s\u1ee3i d\u00e2y \u0111\u00e0n h\u1ed3i c\u0103ng ngang, hai \u0111\u1ea7u c\u1ed1 \u0111\u1ecbnh. Tr\u00ean d\u00e2y c\u00f3 s\u00f3ng d\u1eebng, t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng kh\u00f4ng \u0111\u1ed5i. Khi t\u1ea7n s\u1ed1 s\u00f3ng tr\u00ean d\u00e2y l\u00e0 42 Hz th\u00ec tr\u00ean d\u00e2y c\u00f3 4 \u0111i\u1ec3m b\u1ee5ng. N\u1ebfu tr\u00ean d\u00e2y c\u00f3 6 \u0111i\u1ec3m b\u1ee5ng th\u00ec t\u1ea7n s\u1ed1 s\u00f3ng tr\u00ean d\u00e2y l\u00e0<\/p>\n\n\n\n A<\/td>\n 126 Hz.<\/td>\n B.<\/td>\n 252 Hz.<\/td>\n C.<\/td>\n 28 Hz.<\/td>\n D.<\/td>\n 63 Hz.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n C\u00e2u 44: M\u1ed9t ch\u1ea5t \u0111i\u1ec3m dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a tr\u00ean tr\u1ee5c Ox. Khi ch\u1ea5t \u0111i\u1ec3m \u0111i qua v\u1ecb tr\u00ed c\u00e2n b\u1eb1ng th\u00ec t\u1ed1c \u0111\u1ed9 c\u1ee7a n\u00f3 l\u00e0 20 cm\/s. Khi ch\u1ea5t \u0111i\u1ec3m c\u00f3 t\u1ed1c \u0111\u1ed9 l\u00e0 10 cm\/s th\u00ec gia t\u1ed1c c\u1ee7a n\u00f3 c\u00f3 \u0111\u1ed9 l\u1edbn l\u00e0 cm\/s2<\/sup>. Bi\u00ean \u0111\u1ed9 dao \u0111\u1ed9ng c\u1ee7a ch\u1ea5t \u0111i\u1ec3m l\u00e0<\/p>\n\n\n\n A<\/td>\n 10 cm.<\/td>\n B.<\/td>\n 4 cm.<\/td>\n C.<\/td>\n 8 cm.<\/td>\n D.<\/td>\n 5 cm.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n <\/a><\/p>\n <\/a><\/p>\n","protected":false},"excerpt":{"rendered":" T\u1ed5ng h\u1ee3p 50 c\u00e2u tr\u1eafc nghi\u1ec7m \u0111\u1ec1 thi th\u1eed m\u00f4n v\u1eadt l\u00fd 2017,\u00a0\u0111\u00e2y l\u00e0 t\u00e0i li\u1ec7u tham kh\u1ea3o gi\u00fap c\u00e1c b\u1ea1n chu\u1ea9n b\u1ecb th\u1eadt t\u1ed1t v\u1ec1 ki\u1ebfn th\u1ee9c v\u00e0 k\u1ef9 n\u0103ng l\u00e0m d\u1ea1ng \u0111\u1ec1 tr\u1eafc nghi\u1ec7m m\u00f4n v\u1eadt l\u00fd. M\u00f4n: V\u1eacT L\u00cd (Th\u1eddi gian l\u00e0m b\u00e0i : 90 ph\u00fat; 50 c\u00e2u tr\u1eafc nghi\u1ec7m) Cho: h\u1eb1ng […]<\/p>\n","protected":false},"author":2,"featured_media":311,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[158],"tags":[],"yoast_head":"\n