C\u00e2u 7:<\/b>\u00a0M\u1ed9t song d\u1ecdc truy\u1ec1n theo \u0111\u01b0\u1eddng th\u1eb3ng. Ph\u01b0\u01a1ng tr\u00ecnh dao \u0111\u1ed9ng c\u1ee7a ngu\u1ed3n s\u00f3ng t\u1ea1i O l\u00e0:<\/p>\n

<\/p>\n

\u0110i\u1ec3m M c\u00e1ch ngu\u1ed3n O m\u1ed9t kho\u1ea3ng b\u1eb1ng 1\/3 b\u01b0\u1edbc s\u00f3ng \u1edf th\u1eddi \u0111i\u1ec3m t = T\/2 c\u00f3 dao \u0111\u1ed9ng v\u1edbi li \u0111\u1ed9 u = 2 cm. Bi\u00ean \u0111\u1ed9 s\u00f3ng t\u1ea1i \u0111i\u1ec3m n\u00e0y b\u1eb1ng<\/p>\n

A. 2\u221a3 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 2\u221a2 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 4 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 4\u221a3 cm.<\/p>\n

C\u00e2u 8:<\/b>\u00a0M\u1ed9t ngu\u1ed3n s\u00f3ng dao \u0111\u1ed9ng t\u1ea1o ra t\u1ea1i O tr\u00ean m\u1eb7t ph\u1eb3ng l\u1ea1ng m\u1ed9t dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a theo phu\u00f4ng vu\u00f4ng g\u00f3c v\u1edbi m\u1eb7t n\u01b0\u1edbc . Tr\u00ean m\u1eb7t n\u01b0\u1edbc xu\u1ea5t hi\u1ec7n nh\u1eefng g\u1ee3n s\u00f3ng tr\u00f2n \u0111\u1ed3ng t\u00e2m O c\u00e1ch nhau nh\u1eefng kho\u1ea3ng 2 cm. Bi\u1ebft r\u1eb1ng n\u0103ng l\u01b0\u1ee3ng s\u00f3ng truy\u1ec1n \u0111i kh\u00f4ng m\u1ea5t m\u00e1t do ma s\u00e1t v\u00e0 s\u1ee9c c\u1ea3n c\u1ee7a m\u00f4i tr\u01b0\u1eddng nh\u01b0ng ph\u00e2n b\u1ed1 \u0111\u1ec1u tr\u00ean m\u1eaft s\u00f3ng trong. T\u1ea1i M c\u00e1ch O m\u1ed9t kho\u1ea3ng 1 cm c\u00f3 ph\u01b0\u01a1ng tr\u00ecnh dao \u0111\u1ed9ng u_{M<\/sub>=2cos\u2061(100\u03c0t) (cm). Ph\u01b0\u01a1ng tr\u00ecnh dao \u0111\u1ed9ng t\u1ea1i \u0111i\u1ec3m N tr\u00ean \u0111\u01b0\u1eddng OM, c\u00f9ng ph\u00eda v\u1edbi M so v\u1edbi ngu\u1ed3n O, c\u00e1ch O m\u1ed9t kho\u1ea3ng 2 cm l\u00e0:<\/p>\n}

A. u_{N<\/sub>=\u221a2 cos\u2061(100\u03c0t+\u03c0) (cm)<\/p>\n}

B. u_{N<\/sub>=2 cos\u2061(100\u03c0t+\u03c0) (cm)<\/p>\n}

C. u_{N<\/sub>=2 cos\u2061(100\u03c0t-\u03c0) (cm)<\/p>\n}

D. u_{N<\/sub>=\u221a2 cos\u2061(100\u03c0t-\u03c0) (cm).<\/p>\n}

C\u00e2u 9:<\/b>\u00a0M\u1ed9t s\u1ee3i d\u00e2y m\u1ea3nh \u0111\u00e0n h\u1ed3i, r\u1ea5t d\u00e0i c\u0103ng ngang c\u00f3 \u0111\u1ea7u A dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a v\u1edbi t\u1ea7n s\u1ed1 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c trong kho\u1ea3ng t\u1eeb 45 Hz \u0111\u1ebfn 70 Hz. S\u00f3ng t\u1ea1o th\u00e0nh lan truy\u1ec1n tr\u00ean d\u00e2y v\u1edbi t\u1ed1c \u0111\u1ed9 5 m\/s. \u0110i\u1ec3m M tr\u00ean d\u00e2y c\u00e1ch \u0111\u1ea7u A m\u1ed9t kho\u1ea3ng b\u1eb1ng 20 cm lu\u00f4n dao \u0111\u1ed9ng ng\u01b0\u1ee3c pha v\u1edbi A th\u00ec t\u1ea7n s\u1ed1 c\u00f3 gi\u00e1 tr\u1ecb l\u00e0<\/p>\n

A. 62,5 Hz. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 48,5 Hz. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 56,2 Hz. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 68,1 Hz.<\/p>\n

C\u00e2u 10:<\/b>\u00a0M\u1ed9t s\u00f3ng c\u01a1 lan truy\u1ec1n tr\u00ean m\u1eb7t m\u1ed9t ch\u1ea5t l\u1ecfng v\u1edbi bi\u00ean \u0111\u1ed9 3 cm. T\u1ec9 s\u1ed1 gi\u1eefa t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng v\u00e0 t\u1ed1c \u0111\u1ed9 dao \u0111\u1ed9ng c\u1ef1c \u0111\u1ea1i c\u1ee7a ph\u1ea7n t\u1eed s\u00f3ng l\u00e0 1,2\u03c0. L\u1ea5y \u03c0^{2<\/sup>\u00a0= 10. \u1ede c\u00f9ng m\u1ed9t th\u1eddi \u0111i\u1ec3m, hai ph\u1ea7n t\u1eed s\u00f3ng t\u1ea1i hai th\u1eddi \u0111i\u1ec3m tr\u00ean c\u00f9ng h\u01b0\u1edbng truy\u1ec1n s\u00f3ng c\u00e1ch nhau 2,25 m th\u00ec dao \u0111\u1ed9ng l\u1ec7ch pha nhau<\/p>\n}

<\/p>\n

C\u00e2u 11:<\/b>\u00a0Tr\u00ean m\u1eb7t n\u01b0\u1edbc ph\u1eb3ng n\u1eb1m ngang, c\u00f3 m\u1ed9t ngu\u1ed3n dao \u0111\u1ed9ng \u0111i\u1ec1u h\u00f2a theo ph\u01b0\u01a1ng th\u1eb3ng \u0111\u1ee9ng v\u1edbi t\u1ea7n s\u1ed1 200 Hz. Kho\u1ea3ng c\u00e1ch t\u1eeb g\u1ee3n s\u00f3ng th\u1ee9 nh\u1ea5t \u0111\u1ebfn g\u1ee3n s\u00f3ng th\u1ee9 n\u0103m l\u00e0 1,6 cm. T\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng tr\u00ean m\u1eb7t n\u01b0\u1edbc l\u00e0<\/p>\n

A. 2 m\/s \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 1 m\/s \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C.16 m\/s \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 0,8 m\/s.<\/p>\n

H\u01b0\u1edbng d\u1eabn gi\u1ea3i v\u00e0 \u0111\u00e1p \u00e1n<\/b><\/p>\n\n\n\n\n

C\u00e2u<\/td>\n	7<\/td>\n	8<\/td>\n	9<\/td>\n	10<\/td>\n	11<\/td>\n<\/tr>\n
\u0110\u00e1p \u00e1n<\/td>\n	C<\/td>\n	D<\/td>\n	A<\/td>\n	D<\/td>\n	D<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n C\u00e2u 7:<\/b>\u00a0C<\/p>\n <\/p>\n C\u00e2u 8:<\/b>\u00a0D<\/p>\n <\/p>\n C\u00e2u 9:<\/b>\u00a0A<\/p>\n <\/p>\n C\u00e2u 10:<\/b>\u00a0D<\/p>\n <\/p>\n C\u00e2u 11:<\/b>\u00a0D<\/p>\n 4\u03bb = 1,6 cm \u21d2 \u03bb = 0,4 cm \u21d2 v = \u03bbf = 0,8 m\/s<\/p>\n","protected":false},"excerpt":{"rendered":" C\u00e2u 7:\u00a0M\u1ed9t song d\u1ecdc truy\u1ec1n theo \u0111\u01b0\u1eddng th\u1eb3ng. Ph\u01b0\u01a1ng tr\u00ecnh dao \u0111\u1ed9ng c\u1ee7a ngu\u1ed3n s\u00f3ng t\u1ea1i O l\u00e0: \u0110i\u1ec3m M c\u00e1ch ngu\u1ed3n O m\u1ed9t kho\u1ea3ng b\u1eb1ng 1\/3 b\u01b0\u1edbc s\u00f3ng \u1edf th\u1eddi \u0111i\u1ec3m t = T\/2 c\u00f3 dao \u0111\u1ed9ng v\u1edbi li \u0111\u1ed9 u = 2 cm. Bi\u00ean \u0111\u1ed9 s\u00f3ng t\u1ea1i \u0111i\u1ec3m n\u00e0y b\u1eb1ng A. 2\u221a3 cm. […]<\/p>\n","protected":false},"author":3,"featured_media":26295,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"tdm_status":"","tdm_grid_status":""},"categories":[158],"tags":[1445,1444],"yoast_head":"\n