C\u00e2u 1:<\/b>\u00a0X\u00e9t s\u00f3ng tr\u00ean m\u1eb7t n\u01b0\u1edbc c\u00f3 b\u01b0\u1edbc s\u00f3ng 48 cm. Hai \u0111i\u1ec3m tr\u00ean c\u00f9ng m\u1ed9t ph\u01b0\u01a1ng truy\u1ec1n s\u00f3ng dao \u0111\u1ed9ng l\u1ec7ch pha nhau \u03c0\/6. Hai \u0111i\u1ec3m n\u00e0y c\u00e1ch nhau m\u1ed9t \u0111o\u1ea1n<\/p>\n
A. 4 m. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 4 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 12 m. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 12 cm.<\/p>\n
C\u00e2u 2:<\/b>\u00a0Trong m\u1ed9t m\u00f4i tr\u01b0\u1eddng c\u00f3 s\u00f3ng c\u01a1 lan truy\u1ec1n v\u1edbi t\u1ea7n s\u1ed1 f = 20 Hz. Bi\u1ebft kho\u1ea3ng c\u00e1ch gi\u1eefa hai \u0111i\u1ec3m dao \u0111\u1ed9ng ng\u01b0\u1ee3c pha tr\u00ean c\u00f9ng ph\u01b0\u01a1ng truy\u1ec1n s\u00f3ng c\u00e1ch nhau 7,5 cm v\u00e0 t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng n\u1eb1m trong kho\u1ea3ng t\u1eeb 55 cm\/s \u0111\u1ebfn 70 cm\/s\/ B\u01b0\u1edbc s\u00f3ng c\u1ee7a s\u00f3ng n\u00e0y l\u00e0<\/p>\n
A. 3,0 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 4,5 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 5,0 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 6,0 cm.<\/p>\n
C\u00e2u 3:<\/b>\u00a0Ngu\u1ed3n s\u00f3ng \u1edf O dao \u0111\u1ed9ng v\u1edbi t\u1ea7n s\u1ed1 100 Hz, dao \u0111\u1ed9ng truy\u1ec1n \u0111i v\u1edbi t\u1ed1c \u0111\u1ed9 25 m\/s tr\u00ean ph\u01b0\u01a1ng Ox. Tr\u00ean ph\u01b0\u01a1ng n\u00e0y c\u00f3 hai \u0111i\u1ec3m P v\u00e0 Q c\u00e1ch nhau 6,25 cm. Coi bi\u00ean \u0111\u1ed9i c\u1ee7a s\u00f3ng l\u00e0 a kh\u00f4ng thay \u0111\u1ed5i khi truy\u1ec1n \u0111i. N\u1ebfu t\u1ea1i th\u1eddi \u0111i\u1ec3m n\u00e0o \u0111\u00f3 t\u1ea1i P c\u00f3 li \u0111\u1ed9 a th\u00ec t\u1ea1i Q c\u00f3 li \u0111\u1ed9 b\u1eb1ng<\/p>\n
A. a. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 0,5a. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 0,5a\u221a2. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 0.<\/p>\n
C\u00e2u 4:<\/b>\u00a0M\u1ed9t s\u00f3ng ngang truy\u1ec1n d\u1ecdc theo tr\u1ee5c Ox v\u1edbi b\u01b0\u1edbc s\u00f3ng \u03bb = 16 cm. Bi\u00ean \u0111\u1ed9 s\u00f3ng l\u00e0 A = 0,5 cm kh\u00f4ng \u0111\u1ed5i. T\u1ec9 s\u1ed1 gi\u1eefa t\u1ed1c \u0111\u1ed9 truy\u1ec1n s\u00f3ng v\u1edbi v\u1eadn t\u00f3c dao \u0111\u1ed9ng c\u1ef1c \u0111\u1ea1i c\u1ee7a ph\u1ea7n t\u1eed m\u00f4i tr\u01b0\u1eddng l\u00e0<\/p>\n
<\/p>\n
C\u00e2u 5:<\/b>\u00a0Ngu\u1ed3n \u0111i\u1ec3m O dao \u0111\u1ed9ng v\u1edbi ph\u01b0\u01a1ng tr\u00ecnh<\/p>\n
<\/p>\n
t\u1ea1o ra m\u1ed9t s\u00f3ng c\u01a1 lan truy\u1ec1n tr\u00ean m\u1ed9t s\u1ee3i day d\u00e0i c\u00f3 bi\u00ean \u0111\u1ed9 s\u00f3ng kh\u00f4ng \u0111\u1ed5i. M\u1ed9t \u0111i\u1ec3m M c\u00e1ch ngu\u1ed3n b\u1eb1ng 1\/3 b\u01b0\u1edbc s\u00f3ng \u1edf th\u1eddi \u0111i\u1ec3m t= T\/2 c\u00f3 li \u0111\u1ed9 uM<\/sub>\u00a0= 1,5 cm. Bi\u00ean \u0111\u1ed9 s\u00f3ng c\u00f3 gi\u00e1 tr\u1ecb l\u00e0<\/p>\n A. 1,5 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 3 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 1,5\u221a2 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 1,5\u221a3 cm.<\/p>\n C\u00e2u 6:<\/b>\u00a0M\u1ed9t ngu\u1ed3n O ph\u00e1t s\u00f3ng c\u01a1 dao \u0111\u1ed9ng theo ph\u01b0\u01a1ng tr\u00ecnh u=2cos\u2061(20\u03c0t+\u03c0\/3) (trong \u0111\u00f3 u t\u00ednh b\u1eb1ng milim\u00e9t, t t\u00ednh b\u1eb1ng gi\u00e2y). S\u00f3ng truy\u1ec1n theo \u0111\u01b0\u1eddng th\u1eb3ng Ox v\u1edbi t\u1ed1c \u0111\u1ed9 kh\u00f4ng \u0111\u1ed5i b\u1eb1ng 1 m\/s. M l\u00e0 m\u1ed9t \u0111i\u1ec3m tr\u00ean \u0111\u01b0\u1eddng tr\u1ec1n c\u00e1ch O m\u1ed9t kho\u1ea3ng b\u1eb1ng 42,5 cn. Trong kho\u1ea3ng O \u0111\u1ebfn M s\u1ed1 \u0111i\u1ec3m dao \u0111\u1ed9ng l\u1ec7ch pha \u03c0\/6 v\u1edbi ngu\u1ed3n l\u00e0<\/p>\n A. 9 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 4 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 5 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 8.<\/p>\n H\u01b0\u1edbng d\u1eabn gi\u1ea3i v\u00e0 \u0111\u00e1p \u00e1n<\/b><\/p>\n C\u00e2u 1:<\/b>\u00a0B<\/p>\n <\/p>\n C\u00e2u 2:<\/b>\u00a0A<\/p>\n <\/p>\n C\u00e2u 3:<\/b>\u00a0D<\/p>\n \u03bb= v\/f=25 cm ;PQ= \u03bb\/4 n\u00ean Q dao \u0111\u1ed9ng l\u1ec7ch pha \u03c0\/2 \u0111\u1ed1i v\u1edbi P v\u00e0 c\u00f3 bi\u00ean \u0111\u1ed9 b\u1eb1ng 0<\/p>\n C\u00e2u 4:<\/b>\u00a0B<\/p>\n <\/p>\n C\u00e2u 5:<\/b>\u00a0B<\/p>\n <\/p>\n C\u00e2u 6:<\/b>\u00a0C<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" C\u00e2u 1:\u00a0X\u00e9t s\u00f3ng tr\u00ean m\u1eb7t n\u01b0\u1edbc c\u00f3 b\u01b0\u1edbc s\u00f3ng 48 cm. Hai \u0111i\u1ec3m tr\u00ean c\u00f9ng m\u1ed9t ph\u01b0\u01a1ng truy\u1ec1n s\u00f3ng dao \u0111\u1ed9ng l\u1ec7ch pha nhau \u03c0\/6. Hai \u0111i\u1ec3m n\u00e0y c\u00e1ch nhau m\u1ed9t \u0111o\u1ea1n A. 4 m. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0B. 4 cm. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0C. 12 m. \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0D. 12 cm. C\u00e2u 2:\u00a0Trong m\u1ed9t m\u00f4i tr\u01b0\u1eddng c\u00f3 s\u00f3ng c\u01a1 lan truy\u1ec1n v\u1edbi […]<\/p>\n","protected":false},"author":3,"featured_media":26303,"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\n\n
\n C\u00e2u<\/td>\n 1<\/td>\n 2<\/td>\n 3<\/td>\n 4<\/td>\n 5<\/td>\n 6<\/td>\n<\/tr>\n \n \u0110\u00e1p \u00e1n<\/td>\n B<\/td>\n A<\/td>\n D<\/td>\n B<\/td>\n B<\/td>\n C<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n