{"segment":[{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"\u00c2m kh\u00f4ng th\u1ec3 truy\u1ec1n trong m\u00f4i tr\u01b0\u1eddng n\u00e0o sau \u0111\u00e2y:","select":["A. T\u01b0\u1eddng g\u1ed7.","B. T\u1ea5m r\u00e8m.","C. C\u00e1i b\u00e0n.","D. Kho\u1ea3ng ch\u00e2n kh\u00f4ng."],"hint":"","explain":"<span class='basic_left'>\u00c2m kh\u00f4ng th\u1ec3 truy\u1ec1n trong m\u00f4i tr\u01b0\u1eddng ch\u00e2n kh\u00f4ng.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":2271},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"\u00c2m thanh c\u00f3 th\u1ec3 truy\u1ec1n \u0111\u01b0\u1ee3c trong m\u00f4i tr\u01b0\u1eddng n\u00e0o sau \u0111\u00e2y?","select":["A. Ch\u1ea5t r\u1eafn.","B. Ch\u1ea5t l\u1ecfng.","C. Ch\u1ea5t kh\u00ed.","D. C\u1ea3 ba \u0111\u00e1p \u00e1n tr\u00ean."],"hint":"","explain":"<span class='basic_left'>\u00c2m thanh c\u00f3 th\u1ec3 truy\u1ec1n \u0111\u01b0\u1ee3c trong c\u1ea3 ba m\u00f4i tr\u01b0\u1eddng r\u1eafn, l\u1ecfng v\u00e0 kh\u00ed.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":2272},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"N\u0103m 1994, m\u1ed9t sao ch\u1ed5i \u0111\u00e3 \u0111\u00e2m v\u00e0o sao M\u1ed9c g\u00e2y ra m\u1ed9t v\u1ee5 n\u1ed5 r\u1ea5t l\u1edbn. \u1ede m\u1eb7t \u0111\u1ea5t ta kh\u00f4ng nghe ti\u1ebfng n\u1ed5 v\u00ec: ","select":["A. Tr\u00e1i \u0110\u1ea5t \u1edf r\u1ea5t xa sao M\u1ed9c.","B. Gi\u1eefa Tr\u00e1i \u0110\u1ea5t v\u00e0 sao M\u1ed9c l\u00e0 ch\u00e2n kh\u00f4ng. ","C. \u00c2m thanh t\u1eeb Tr\u00e1i \u0110\u1ea5t \u0111\u1ebfn sao M\u1ed9c ph\u1ea3i m\u1ea5t 60 n\u0103m.","D. \u00c2m thanh \u0111\u00e3 b\u1ecb b\u1ea7u kh\u00ed quy\u1ec3n h\u1ea5p th\u1ee5."],"hint":"","explain":"<span class='basic_left'>\u1ede m\u1eb7t \u0111\u1ea5t ta kh\u00f4ng nghe ti\u1ebfng n\u1ed5 v\u00ec gi\u1eefa Tr\u00e1i \u0110\u1ea5t v\u00e0 sao M\u1ed9c l\u00e0 ch\u00e2n kh\u00f4ng, m\u00e0 \u00e2m kh\u00f4ng th\u1ec3 truy\u1ec1n trong m\u00f4i tr\u01b0\u1eddng ch\u00e2n kh\u00f4ng.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":1}]}],"id_ques":2273},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"V\u1eadn t\u1ed1c \u00e2m thanh truy\u1ec1n trong kh\u00f4ng kh\u00ed \u1edf 20 \u0111\u1ed9 l\u00e0:","select":["A. 340m\/s.","B. 500m\/s.","C. 200m\/s.","D. 100m\/s."],"hint":"","explain":"<span class='basic_left'>V\u1eadn t\u1ed1c \u00e2m thanh truy\u1ec1n trong kh\u00f4ng kh\u00ed \u1edf 20 \u0111\u1ed9 l\u00e0 340m\/s.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2274},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang:","select":["A. V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t r\u1eafn l\u1edbn h\u01a1n ch\u1ea5t kh\u00ed, v\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t kh\u00ed l\u1edbn h\u01a1n ch\u1ea5t l\u1ecfng","B. V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t r\u1eafn l\u1edbn h\u01a1n ch\u1ea5t l\u1ecfng, v\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t l\u1ecfng l\u1edbn h\u01a1n ch\u1ea5t kh\u00ed.","C. V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t l\u1ecfng l\u1edbn nh\u1ea5t. ","D. V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t kh\u00ed l\u1edbn h\u01a1n ch\u1ea5t l\u1ecfng, v\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t l\u1ecfng l\u1edbn h\u01a1n ch\u1ea5t r\u1eafn."],"hint":"","explain":"<span class='basic_left'>V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t r\u1eafn l\u1edbn h\u01a1n ch\u1ea5t l\u1ecfng, v\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t l\u1ecfng l\u1edbn h\u01a1n ch\u1ea5t kh\u00ed. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":1}]}],"id_ques":2275},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"\u1ede tr\u00ean c\u00e1c n\u00fai cao, khi g\u1ecdi nhau kh\u00f3 nghe h\u01a1n \u1edf ch\u00e2n n\u00fai v\u00ec:","select":["A. Kh\u00f4ng kh\u00ed \u1edf tr\u00ean cao l\u1ea1nh, n\u00ean truy\u1ec1n \u00e2m k\u00e9m h\u01a1n.","B. \u1ede tr\u00ean cao n\u1eafng h\u01a1n n\u00ean truy\u1ec1n \u00e2m k\u00e9m h\u01a1n.","C. Kh\u00f4ng kh\u00ed \u1edf tr\u00ean cao lo\u00e3ng h\u01a1n, n\u00ean truy\u1ec1n \u00e2m k\u00e9m h\u01a1n.","D. \u1ede tr\u00ean cao gi\u00f3 c\u1ea3n tr\u1edf vi\u1ec7c truy\u1ec1n \u00e2m."],"hint":"","explain":"<span class='basic_left'>Do s\u1ef1 truy\u1ec1n \u00e2m d\u1ef1a v\u00e0o s\u1ef1 truy\u1ec1n dao \u0111\u1ed9ng c\u1ee7a c\u00e1c h\u1ea1t n\u00ean khi kh\u00f4ng kh\u00ed lo\u00e3ng t\u1ee9c l\u00e0 c\u00e1c h\u1ea1t \u00edt h\u01a1n th\u00ec s\u1ef1 truy\u1ec1n \u00e2m k\u00e9m h\u01a1n.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":2276},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"\u00c2m truy\u1ec1n trong kh\u00f4ng kh\u00ed \u0111\u1ea1i l\u01b0\u1ee3ng n\u00e0o sau \u0111\u00e2y kh\u00f4ng \u0111\u1ed5i:","select":["A. \u0110\u1ed9 to c\u1ee7a \u00e2m.","B. \u0110\u1ed9 cao c\u1ee7a \u00e2m.","C. Bi\u00ean \u0111\u1ed9 c\u1ee7a \u00e2m","D. Ca\u0301c c\u00e2u tra\u0309 l\u01a1\u0300i A,B,C \u0111\u00ea\u0300u \u0111u\u0301ng."],"hint":"","explain":"<span class='basic_left'>Kh\u00f4ng kh\u00ed s\u1ebd h\u1ea5p th\u1ee5 l\u00e0m gi\u1ea3m bi\u00ean \u0111\u1ed9 c\u0169ng nh\u01b0 \u0111\u1ed9 to c\u1ee7a \u00e2m.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2277},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"T\u1ea1i sao khi s\u00e9t \u0111\u00e1nh ta nh\u00ecn th\u1ea5y tia ch\u1edbp tr\u01b0\u1edbc v\u00e0i gi\u00e2y sau m\u1edbi nghe th\u1ea5y ti\u1ebfng s\u1ea5m: ","select":["A. V\u00ec v\u1eadn t\u1ed1c c\u1ee7a \u00e1nh s\u00e1ng truy\u1ec1n trong kh\u00f4ng kh\u00ed l\u1edbn h\u01a1n v\u1eadn t\u1ed1c c\u1ee7a \u00e2m thanh.","B. V\u00ec \u00e2m thanh t\u1ea1o ra sau \u00e1nh s\u00e1ng.","C. V\u00ec \u00e2m thanh kh\u00f4ng truy\u1ec1n \u0111\u01b0\u1ee3c trong kh\u00f4ng kh\u00ed.","D. V\u00ec ch\u1edbp c\u00f3 tr\u01b0\u1edbc sau \u0111\u1ea5y m\u1edbi c\u00f3 \u00e2m thanh."],"hint":"","explain":"<span class='basic_left'>Tia ch\u1edbp v\u00e0 \u00e2m thanh \u0111\u01b0\u1ee3c t\u1ea1o ra g\u1ea7n nh\u01b0 \u0111\u1ed3ng th\u1eddi, nh\u01b0ng do v\u1eadn t\u1ed1c c\u1ee7a \u00e1nh s\u00e1ng truy\u1ec1n trong kh\u00f4ng kh\u00ed l\u00e0 300000000m\/s l\u1edbn h\u01a1n r\u1ea5t nh\u1ec1u l\u1ea7n so v\u1edbi v\u1eadn t\u1ed1c \u00e2m thanh trong kh\u00f4ng kh\u00ed n\u00ean ta nh\u00ecn h\u1ea5y tia s\u00e1ng tr\u01b0\u1edbc sau \u0111\u00f3 m\u1edbi nghe th\u1ea5y \u00e2m thanh.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":2278},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"V\u00ec sao khi c\u00f3 ng\u01b0\u1eddi \u0111\u1ebfn b\u1edd s\u00f4ng c\u00e1 ngay l\u1eadp t\u1ee9c l\u1ea9n tr\u1ed1n \u0111i?","select":["A. V\u00ec c\u00e1 nh\u00ecn th\u1ea5y ng\u01b0\u1eddi.","B. V\u00ec c\u00e1 bi\u1ebft l\u00e0 b\u1ecb b\u1eaft.","C. V\u00ec c\u00e1 \u0111i ch\u1ed7 kh\u00e1c ki\u1ebfm m\u1ed3i.","D. V\u00ec c\u00e1 nghe th\u1ea5y \u00e2m thanh b\u01b0\u1edbc ch\u00e2n ng\u01b0\u1eddi \u0111\u1ebfn g\u1ea7n."],"hint":"","explain":"<span class='basic_left'>V\u00ec \u00e2m thanh t\u1eeb b\u01b0\u1edbc ch\u00e2n ng\u01b0\u1eddi truy\u1ec1n qua \u0111\u1ea5t tr\u00ean b\u1edd, qua n\u01b0\u1edbc r\u1ed3i \u0111\u1ebfn tai c\u00e1.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":2279},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"M\u1ed9t ng\u01b0\u1eddi nghe th\u1ea5y ti\u1ebfng s\u1ea5m sau tia ch\u1edbp 4s, h\u1ecfi ng\u01b0\u1eddi \u0111\u00f3 c\u00e1ch n\u01a1i x\u1ea3y ra s\u00e9t bao xa?","select":["A. 1360 m","B. 1400 m","C. 1200 m","D. T\u1ea5t c\u1ea3 \u0111\u1ec1u sai"],"hint":"","explain":"<span class='basic_left'>V\u00ec v\u1eadn t\u1ed1c c\u1ee7a \u00e1nh s\u00e1ng truy\u1ec1n trong kh\u00f4ng kh\u00ed r\u1ea5t l\u1edbn n\u00ean coi nh\u01b0 ng\u01b0\u1eddi \u0111\u00f3 nh\u00ecn th\u1ea5y tia ch\u1edbp ngay khi n\u00f3 x\u1ea3y ra.<br\/>Ta c\u00f3 v\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong kh\u00f4ng kh\u00ed l\u00e0 340m\/s, th\u1eddi gian l\u00e0 4s. Kho\u1ea3ng c\u00e1ch l\u00e0 340 x 4 = 1360m<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2280},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"Khi \u1edf xa ta nh\u00ecn th\u1ea5y m\u1ed9t ng\u01b0\u1eddi \u0111\u00e1nh tr\u1ed1ng v\u00e0 sau 2s m\u1edbi nghe th\u1ea5y ti\u1ebfng tr\u1ed1ng. Kho\u1ea3ng c\u00e1ch t\u1eeb tr\u1ed1ng \u0111\u1ebfn ta l\u00e0 :","select":["A. 1000m","B. 680m","C. 700m","D. 1360m"],"hint":"","explain":"<span class='basic_left'>V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong kh\u00f4ng kh\u00ed 340m\/s.<br\/>Kho\u1ea3ng c\u00e1ch l\u00e0: 340 x 2 = 680m.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2281},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Khi g\u00f5 v\u00e0o m\u1ed9t \u0111\u1ea7u \u1ed1ng kim lo\u1ea1i d\u00e0i, ng\u01b0\u1eddi \u0111\u1ee9ng \u0111\u1ea7u kia \u1ed1ng nghe th\u1ea5y 2 \u00e2m ph\u00e1t ra v\u00ec?","select":["A. \u1ed0ng kim lo\u1ea1i lu\u00f4n ph\u00e1t ra 2 \u00e2m v\u00e0 truy\u1ec1n \u0111\u1ebfn tai ta.","B. \u00c2m \u0111\u1ea7u do kim lo\u1ea1i ph\u00e1t ra, \u00e2m sau do v\u1ecdng l\u1ea1i.","C. \u00c2m \u0111\u1ea7u do kim lo\u1ea1i truy\u1ec1n \u0111i, \u00e2m sau do kh\u00f4ng kh\u00ed truy\u1ec1n \u0111i.","D. \u00c2m c\u00f3 t\u1ea7n s\u1ed1 cao truy\u1ec1n tr\u01b0\u1edbc, \u00e2m tr\u1ea7m truy\u1ec1n sau."],"hint":"","explain":"<span class='basic_left'>Do ch\u1ea5t r\u1eafn truy\u1ec1n \u00e2m thanh nhanh h\u01a1n ch\u1ea5t kh\u00ed, cho n\u00ean \u00e2m thanh s\u1ebd truy\u1ec1n theo \u1ed1ng kim lo\u1ea1i \u0111\u1ebfn tai ng\u01b0\u1eddi nghe \u0111\u1ea7u ti\u00ean sau \u0111\u00f3 nghe \u0111\u01b0\u1ee3c ti\u1ebfng th\u1ee9 hai do kh\u00f4ng kh\u00ed truy\u1ec1n \u0111\u1ebfn.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":2282},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"\u0110i\u1ec1n t\u1eeb th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng:<br\/>Trong c\u00e1c m\u00f4i tr\u01b0\u1eddng kh\u00e1c nhau th\u00ec \u2026\u2026 l\u00e0 kh\u00e1c nhau.","select":["A. V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m.","B. T\u1ea7n s\u1ed1 c\u1ee7a \u00e2m.","C. \u0110\u1ed9 cao c\u1ee7a \u00e2m.","D. C\u1ea3 3 \u0111\u00e1o \u00e1n \u0111\u1ec1u \u0111\u00fang."],"hint":"","explain":"<span class='basic_left'>Trong c\u00e1c m\u00f4i tr\u01b0\u1eddng kh\u00e1c nhau th\u00ec v\u1eadn t\u1ed1c truy\u1ec1n \u00e2m l\u00e0 kh\u00e1c nhau.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2283},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"Ch\u1ea5t n\u00e0o sau \u0111\u00e2y truy\u1ec1n \u00e2m nhanh nh\u1ea5t?","select":["A. N\u01b0\u1edbc bi\u1ec3n.","B. Kh\u00f4ng kh\u00ed.","C. N\u01b0\u1edbc g\u1ea1o.","D. M\u1eb7t \u0111\u1ea5t."],"hint":"","explain":"<span class='basic_left'>V\u00ec v\u1eadn t\u1ed1c c\u1ee7a \u00e2m thanh trong ch\u1ea5t r\u1eafn l\u1edbn h\u01a1n trong ch\u1ea5t l\u1ecfng v\u00e0 ch\u1ea5t kh\u00ed.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":2284},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Trong m\u1ed9t m\u00f4i tr\u01b0\u1eddng c\u1ee9 5s th\u00ec \u00e2m thanh \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i m\u1ed9t kho\u1ea3ng l\u00e0 7.5km th\u00ec \u0111\u00f3 l\u00e0 m\u00f4i tr\u01b0\u1eddng n\u00e0o?","select":["A. Kh\u00f4ng kh\u00ed","B. Th\u00e9p","C. N\u01b0\u1edbc","D. \u0110\u1ea5t"],"hint":"","explain":"<span class='basic_left'>V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m: $\\dfrac{7500}{5}=1500 m\/s$.<br\/>L\u00e0 v\u1eadn t\u1ed1c c\u1ee7a m\u00f4i tr\u01b0\u1eddng n\u01b0\u1edbc.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2285},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":"L\u00fac 7h t\u1ea1i m\u1ed9t nh\u00e0 ga A c\u00f3 m\u1ed9t \u0111o\u00e0n t\u00e0u \u0111ang b\u1eaft \u0111\u1ea7u kh\u1edfi h\u00e0nh, c\u00f3 m\u1ed9t ng\u01b0\u1eddi c\u00e1ch nh\u00e0 ga 18,3 km \u00e1p s\u00e1t tai v\u00e0o \u0111\u01b0\u1eddng ray th\u00ec sau bao l\u00e2u ng\u01b0\u1eddi \u0111\u00f3 nghe \u0111\u01b0\u1ee3c ti\u1ebfng chuy\u1ec3n \u0111\u1ed9ng c\u1ee7a \u0111o\u00e0n t\u00e0u? Bi\u1ebft v\u1eadn t\u1ed1c \u00e2m thanh truy\u1ec1n trong \u0111\u01b0\u1eddng ray l\u00e0 6100 m\/s.","select":["A. 3s","B. 4s","C. 5s","D. 6s"],"hint":"","explain":"<span class='basic_left'>Th\u1eddi gian t\u1eeb l\u00fac t\u00e0u kh\u1edfi h\u00e0nh \u0111\u1ebfn l\u00fac ng\u01b0\u1eddi \u0111\u00f3 nghe \u0111\u01b0\u1ee3c \u00e2m thanh l\u00e0: $\\dfrac{18300}{6100}=3s$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2286},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong v\u1eadt li\u1ec7u n\u00e0o nh\u1ecf nh\u1ea5t?","select":["A. N\u01b0\u1edbc","B. Th\u00e9p ","C. Kh\u00f4ng kh\u00ed ","D. M\u1eb7t \u0111\u1ea5t"],"hint":"","explain":"<span class='basic_left'>V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong ch\u1ea5t kh\u00ed nh\u1ecf h\u01a1n trong ch\u1ea5t l\u1ecfng, ch\u1ea5t r\u1eafn.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2287},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":"M\u1ed9t ng\u01b0\u1eddi \u0111\u1ee9ng c\u00e1ch m\u1ed9t c\u00e1i tr\u1ed1ng 680m, c\u1ea7n bao l\u00e2u \u0111\u1ec3 ng\u01b0\u1eddi \u0111\u00f3 nghe th\u1ea5y \u00e2m thanh sau khi \u0111\u00e1nh tr\u1ed1ng?","select":["A. 1s","B. 2s","C. 0.2s","D. 10s"],"hint":"","explain":"<span class='basic_left'>Th\u1eddi gian \u0111\u1ec3 ng\u01b0\u1eddi \u0111\u00f3 nghe th\u1ea5y ti\u1ebfng tr\u1ed1ng l\u00e0: $\\dfrac{680}{340}=2s$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2288},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"\u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c \u0111i l\u00e0 do?","select":["A. Kh\u00f4ng kh\u00ed kh\u00f4ng h\u1ea5p th\u1ee5 \u00e2m thanh.","B. \u00c2m thanh kh\u00f4ng b\u1ecb hao.","C. S\u1ef1 truy\u1ec1n dao \u0111\u1ed9ng c\u1ee7a c\u00e1c h\u1ea1t v\u1eadt ch\u1ea5t trong m\u00f4i tr\u01b0\u1eddng. ","D. Ch\u1ea5t r\u1eafn h\u1ea5p th\u1ee5 \u00e2m thanh."],"hint":"","explain":"<span class='basic_left'>\u00c2m thanh truy\u1ec1n \u0111\u01b0\u1ee3c \u0111i l\u00e0 do s\u1ef1 truy\u1ec1n dao \u0111\u1ed9ng c\u1ee7a c\u00e1c h\u1ea1t v\u1eadt ch\u1ea5t trong m\u00f4i tr\u01b0\u1eddng. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":2289},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":5,"ques":"C\u00e0ng g\u1ea7n ngu\u1ed3n \u00e2m th\u00ec \u00e2m nghe c\u00e0ng.....","select":["A. Nh\u1ecf","B. Cao","C. Th\u1ea5p ","D. To"],"hint":"","explain":"<span class='basic_left'>C\u00e0ng g\u1ea7n ngu\u1ed3n \u00e2m th\u00ec \u00e2m nghe c\u00e0ng to, v\u00ec g\u1ea7n ngu\u1ed3n \u00e2m th\u00ec bi\u00ean \u0111\u1ed9 giao \u0111\u1ed9ng \u00e2m l\u1edbn.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":2290}],"lesson":{"save":0,"level":2}}