{"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":" C\u00e1c \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb \u1edf trong l\u00f2ng \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u ch\u1ea1y qua c\u00f3 nh\u1eefng \u0111\u1eb7c \u0111i\u1ec3m g\u00ec?","select":["A. L\u00e0 nh\u1eefng \u0111\u01b0\u1eddng th\u1eb3ng song song, c\u00e1ch \u0111i\u1ec1u nhau v\u00e0 vu\u00f4ng g\u00f3c v\u1edbi tr\u1ee5c c\u1ee7a \u1ed1ng d\u00e2y","B. L\u00e0 nh\u1eefng v\u00f2ng tr\u00f2n c\u00e1ch \u0111\u1ec1u nhau, c\u00f3 t\u00e2m n\u1eb1m tr\u00ean tr\u1ee5c c\u1ee7a \u1ed1ng d\u00e2y.","C. L\u00e0 nh\u1eefng \u0111\u01b0\u1eddng th\u1eb3ng song song, c\u00e1ch \u0111\u1ec1u nhau v\u00e0 h\u01b0\u1edbng t\u1eeb c\u1ef1c B\u1eafc \u0111\u1ebfn c\u1ef1c Nam c\u1ee7a \u1ed1ng d\u00e2y.","D. L\u00e0 nh\u1eefng \u0111\u01b0\u1eddng th\u1eb3ng song song, c\u00e1ch \u0111\u1ec1u nhau v\u00e0 h\u01b0\u1edbng t\u1eeb c\u1ef1c Nam \u0111\u1ebfn c\u1ef1c B\u1eafc c\u1ee7a \u1ed1ng d\u00e2y."],"hint":"","explain":"<span class='basic_left'>B\u00ean trong \u1ed1ng d\u00e2y: L\u00e0 nh\u1eefng \u0111\u01b0\u1eddng th\u1eb3ng song song, c\u00e1ch \u0111\u1ec1u nhau v\u00e0 h\u01b0\u1edbng t\u1eeb c\u1ef1c Nam \u0111\u1ebfn c\u1ef1c B\u1eafc c\u1ee7a \u1ed1ng d\u00e2y.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":3111},{"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":"N\u1ebfu d\u00f9ng quy t\u1eafc n\u1eafm tay ph\u1ea3i \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a t\u1eeb tr\u01b0\u1eddng c\u1ee7a \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua th\u00ec ng\u00f3n tay c\u00e1i cho\u00e3i ra ch\u1ec9 \u0111i\u1ec1u g\u00ec? ","select":["A. Chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n trong \u1ed1ng d\u00e2y.","B. Chi\u1ec1u c\u1ee7a l\u1ef1c \u0111i\u1ec7n t\u1eeb l\u00ean nam ch\u00e2m th\u1eed.","C. Chi\u1ec1u c\u1ee7a l\u1ef1c \u0111i\u1ec7n t\u1eeb t\u00e1c d\u1ee5ng l\u00ean c\u1ef1c B\u1eafc c\u1ee7a nam ch\u00e2m th\u1eed \u0111\u1eb7t \u1edf ngo\u00e0i \u1ed1ng d\u00e2y.","D. Chi\u1ec1u c\u1ee7a l\u1ef1c \u0111i\u1ec7n t\u1eeb t\u00e1c d\u1ee5ng l\u00ean c\u1ef1c B\u1eafc c\u1ee7a nam ch\u00e2m th\u1eed trong l\u00f2ng \u1ed1ng d\u00e2y."],"hint":"","explain":"<span class='basic_left'> Quy t\u1eafc n\u1eafm tay ph\u1ea3i \u201c N\u1eafm b\u00e0n tay ph\u1ea3i, r\u1ed3i \u0111\u1eb7t sao cho b\u1ed1n ng\u00f3n tay h\u01b0\u1edbng theo chi\u1ec1u d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua c\u00e1c v\u00f2ng d\u00e2y th\u00ec ng\u00f3n tay c\u00e1i cho\u00e3i ra ch\u1ec9 chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong l\u00f2ng \u1ed1ng d\u00e2y hay chi\u1ec1u c\u1ee7a l\u1ef1c \u0111i\u1ec7n t\u1eeb t\u00e1c d\u1ee5ng l\u00ean c\u1ef1c B\u1eafc c\u1ee7a nam ch\u00e2m th\u1eed trong l\u00f2ng \u1ed1ng d\u00e2y.\u201d <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":3112},{"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\u00ec sao c\u00f3 th\u1ec3 coi \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u ch\u1ea1y qua nh\u01b0 m\u1ed9t thanh nam ch\u00e2m th\u1eb3ng. ","select":["A. V\u00ec \u1ed1ng d\u00e2y c\u0169ng c\u00f3 t\u00e1c d\u1ee5ng l\u1ef1c t\u1eeb l\u00ean kim nam ch\u00e2m.","B. V\u00ec \u1ed1ng d\u00e2y c\u0169ng t\u00e1c d\u1ee5ng l\u1ef1c t\u1eeb l\u00ean kim s\u1eaft.","C. V\u00ec \u1ed1ng d\u00e2y c\u0169ng c\u00f3 hai c\u1ef1c t\u1eeb nh\u01b0 thanh nam ch\u00e2m.","D. V\u00ec m\u1ed9t kim nam ch\u00e2m \u0111\u1eb7t trong l\u00f2ng \u1ed1ng d\u00e2y c\u0169ng ch\u1ecbu t\u00e1c d\u1ee5ng c\u1ee7a m\u1ed9t l\u1ef1c gi\u1ed1ng nh\u01b0 khi \u0111\u1eb7t trong l\u00f2ng thanh nam ch\u00e2m."],"hint":"","explain":"<span class='basic_left'>C\u00f3 th\u1ec3 coi \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u ch\u1ea1y qua nh\u01b0 m\u1ed9t thanh nam ch\u00e2m th\u1eb3ng v\u00ec: \u201c V\u00ec \u1ed1ng d\u00e2y c\u0169ng c\u00f3 hai c\u1ef1c t\u1eeb nh\u01b0 thanh nam ch\u00e2m.\u201d<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":3113},{"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":" Quy t\u1eafc n\u00e0o d\u01b0\u1edbi \u0111\u00e2y cho ta x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb \u1edf trong l\u00f2ng m\u1ed9t \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u ch\u1ea1y qua?","select":["A. Quy t\u1eafc b\u00e0n tay ph\u1ea3i.","B. Quy t\u1eafc b\u00e0n tay tr\u00e1i.","C. Quy t\u1eafc n\u1eafm tay ph\u1ea3i.","D. Quy t\u1eafc ng\u00f3n tay ph\u1ea3i."],"hint":"","explain":"<span class='basic_left'>Quy t\u1eafc cho ta x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb \u1edf trong l\u00f2ng m\u1ed9t \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n m\u1ed9t chi\u1ec1u ch\u1ea1y qua l\u00e0 quy t\u1eafc n\u1eafm tay ph\u1ea3i: \u201cN\u1eafm b\u00e0n tay ph\u1ea3i, r\u1ed3i \u0111\u1eb7t sao cho b\u1ed1n ng\u00f3n tay h\u01b0\u1edbng theo chi\u1ec1u d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua c\u00e1c v\u00f2ng d\u00e2y th\u00ec ng\u00f3n tay c\u00e1i cho\u00e3i ra ch\u1ec9 chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong l\u00f2ng \u1ed1ng d\u00e2y.\u201d<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3114},{"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":"Quy t\u1eafc n\u00e0o d\u01b0\u1edbi \u0111\u00e2y cho ta x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n ch\u1ea1y trong d\u00e2y d\u1eabn \u1edf trong l\u00f2ng m\u1ed9t \u1ed1ng d\u00e2y c\u00f3 sinh ra t\u1eeb tr\u01b0\u1eddng. ","select":["A. Quy t\u1eafc b\u00e0n tay ph\u1ea3i.","B. Quy t\u1eafc b\u00e0n tay tr\u00e1i.","C. Quy t\u1eafc n\u1eafm tay ph\u1ea3i.","D. Quy t\u1eafc ng\u00f3n tay ph\u1ea3i."],"hint":"","explain":"<span class='basic_left'>Quy t\u1eafc cho ta x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c chi\u1ec1u \u0111\u01b0\u1ee3c chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n ch\u1ea1y trong d\u00e2y d\u1eabn \u1edf trong l\u00f2ng m\u1ed9t \u1ed1ng d\u00e2y c\u00f3 sinh ra t\u1eeb tr\u01b0\u1eddng: Quy t\u1eafc n\u1eafm tay ph\u1ea3i \u201cN\u1eafm b\u00e0n tay ph\u1ea3i, ng\u00f3n tay c\u00e1i cho\u00e3i ra ch\u1ec9 chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong l\u00f2ng \u1ed1ng d\u00e2y, chi\u1ec1u n\u1eafm c\u1ee7a c\u00e1c ng\u00f3n tay ch\u1ec9 chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n ch\u1ea1y trong d\u00e2y d\u1eabn \u1edf trong l\u00f2ng m\u1ed9t \u1ed1ng d\u00e2y.\u201d <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3115},{"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":" \u0110\u1ed9 l\u1edbn c\u1ea3m \u1ee9ng t\u1eeb trong l\u00f2ng m\u1ed9t \u1ed1ng d\u00e2y h\u00ecnh tr\u1ee5 c\u00f3 d\u00f2ng \u0111i\u1ec7n 12 (A) ch\u1ea1y qua v\u00e0 c\u00f3 m\u1eadt \u0111\u1ed9 v\u00f2ng d\u00e2y l\u00e0 5000 l\u00e0: \u201d ","select":["A. 75,4\u03bcT","B. 754 mT","C. 75,4 mT","D. 0,754T"],"hint":"","explain":"<span class='basic_left'>C\u1ea3m \u1ee9ng t\u1eeb trong l\u00f2ng c\u1ee7a \u1ed1ng d\u00e2y c\u00f3 \u0111\u1ed9 l\u1edbn b\u1eb1ng:<br\/>$B=4\\pi \\times {{10}^{-7}}\\times nI=4\\pi \\times {{10}^{-7}}\\times 5000\\times 12=754\\times {{10}^{-4}}T$.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3116},{"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 s\u1ee3i d\u00e2y d\u1eabn d\u00e0i 30cm \u0111\u01b0\u1ee3c qu\u1ea5n th\u00e0nh m\u1ed9t \u1ed1ng d\u00e2y sao cho c\u00e1c v\u00f2ng d\u00e2y n\u1eb1m s\u00e1t nhau, \u0111\u01b0\u1eddng k\u00ednh ti\u1ebft di\u1ec7n \u1ed1ng d\u00e2y d = 5cm. Khi cho d\u00f2ng \u0111i\u1ec7n c\u00f3 c\u01b0\u1eddng \u0111\u1ed9 10A ch\u1ea1y qua \u1ed1ng d\u00e2y th\u00ec c\u1ea3m \u1ee9ng t\u1eeb trong l\u00f2ng \u1ed1ng d\u00e2y \u0111o \u0111\u01b0\u1ee3c b\u1eb1ng$\\pi \\times {{10}^{-3}}T$ . Chi\u1ec1u d\u00e0i c\u1ee7a s\u1ee3i d\u00e2y l\u00e0 ","select":["A. 11,78m ","B. 23,56m","C. 17,18m","D. 25,36m"],"hint":"","explain":"<span class='basic_left'>S\u1ed1 v\u00f2ng d\u00e2y tr\u00ean m\u1ed9t \u0111\u01a1n v\u1ecb chi\u1ec1u d\u00e0i l\u00e0: <br\/> S\u1ed1 v\u00f2ng d\u00e2y l\u00e0: $N=n\\times l=250\\times 0,3=75$v\u00f2ng<br\/> Chi\u1ec1u d\u00e0i c\u1ee7a s\u1ee3i d\u00e2y b\u1eb1ng $L\\text{ }=\\text{ }N\\times \\pi \\times d\\text{ }=\\text{ }75\\times \\pi \\times 0,05\\text{ }=\\text{ }11,78m$ <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3117},{"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":"Qui t\u1eafc n\u1eafm tay ph\u1ea3i d\u00f9ng \u0111\u1ec3 ","select":["A. x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a l\u1ef1c t\u1eeb trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n .","B. x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a l\u1ef1c \u0111i\u1ec7n t\u1eeb . ","C. X\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n . ","D. x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n . "],"hint":"","explain":"<span class='basic_left'>Qui t\u1eafc n\u1eafm tay ph\u1ea3i d\u00f9ng \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n . <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":3118},{"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":"\u0110\u01b0\u1eddng s\u1ee9c t\u1eeb c\u1ee7a \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n c\u00f3 h\u00ecnh d\u1ea1ng l\u00e0 ","select":["A. nh\u1eefng \u0111\u01b0\u1eddng cong k\u00edn . ","B. nh\u1eefng \u0111\u01b0\u1eddng cong h\u1edf ","C. nh\u1eefng \u0111\u01b0\u1eddng tr\u00f2n . ","D. nh\u1eefng \u0111\u01b0\u1eddng th\u1eb3ng song song"],"hint":"","explain":"<span class='basic_left'>\u0110\u01b0\u1eddng s\u1ee9c t\u1eeb c\u1ee7a \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n c\u00f3 h\u00ecnh d\u1ea1ng l\u00e0 nh\u1eefng \u0111\u01b0\u1eddng cong k\u00edn .<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3119},{"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 s\u1eed d\u1ee5ng quy t\u1eafc n\u1eafm tay ph\u1ea3i , ta ph\u1ea3i \u0111\u1eb7t b\u00e0n tay sao cho chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n trong c\u00e1c v\u00f2ng d\u00e2y theo chi\u1ec1u","select":["A. t\u1eeb c\u1ed5 \u0111\u1ebfn ng\u00f3n tay ","B. c\u1ee7a 4 ng\u00f3n tay ","C. xuy\u00ean v\u00e0o l\u00f2ng b\u00e0n tay ","D. c\u1ee7a ng\u00f3n tay c\u00e1i "],"hint":"","explain":"<span class='basic_left'>Khi s\u1eed d\u1ee5ng quy t\u1eafc n\u1eafm tay ph\u1ea3i , ta ph\u1ea3i \u0111\u1eb7t b\u00e0n tay sao cho chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n trong c\u00e1c v\u00f2ng d\u00e2y theo chi\u1ec1u c\u1ee7a 4 ng\u00f3n tay<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3120},{"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 s\u1eed d\u1ee5ng qui t\u1eafc n\u1eafm tay ph\u1ea3i \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong \u1ed1ng d\u00e2y , th\u00ec chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb l\u00e0 chi\u1ec1u","select":["A. xuy\u00ean v\u00e0o l\u00f2ng b\u00e0n tay .","B. t\u1eeb c\u1ed5 tay \u0111\u1ebfn ng\u00f3n tay .","C. c\u1ee7a ng\u00f3n tay c\u00e1i . ","D. c\u1ee7a 4 ng\u00f3n tay . "],"hint":"","explain":"<span class='basic_left'>Khi s\u1eed d\u1ee5ng qui t\u1eafc n\u1eafm tay ph\u1ea3i \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong \u1ed1ng d\u00e2y , th\u00ec chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb l\u00e0 chi\u1ec1u c\u1ee7a ng\u00f3n tay c\u00e1i<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3121},{"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":"Chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ph\u1ee5 thu\u1ed9c ","select":["A. c\u00e1ch qu\u1ea5n \u1ed1ng d\u00e2y ","B. c\u00e1c c\u1ef1c c\u1ee7a \u1ed1ng d\u00e2y ","C. c\u00e1c c\u1ef1c c\u1ee7a nam ch\u00e2m th\u1eed ","D. chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua c\u00e1c v\u00f2ng d\u00e2y "],"hint":"","explain":"<span class='basic_left'>Chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ph\u1ee5 thu\u1ed9c chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua c\u00e1c v\u00f2ng d\u00e2y . <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":3122},{"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":"Nh\u1eadn \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y l\u00e0 \u0111\u00fang khi n\u00f3i v\u1ec1 \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua : ","select":["A. \u1ed0ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n l\u00e0 m\u1ed9t nam ch\u00e2m v\u0129nh c\u1eedu .","B. \u1ed0ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n c\u0169ng c\u00f3 c\u00e1c t\u1eeb c\u1ef1c gi\u1ed1ng nh\u01b0 m\u1ed9t nam ch\u00e2m th\u1eb3ng . ","C. \u0110\u1ea7u c\u00f3 c\u00e1c \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb \u0111i v\u00e0o l\u00e0 t\u1eeb c\u1ef1c b\u1eafc ( N ) c\u1ee7a \u1ed1ng d\u00e2y . ","D. \u0110\u1ea7u c\u00f3 c\u00e1c \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb \u0111i ra l\u00e0 t\u1eeb c\u1ef1c nam ( S ) c\u1ee7a \u1ed1ng d\u00e2y . "],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":1}]}],"id_ques":3123},{"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":"Nh\u1eadn \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y l\u00e0 \u0111\u00fang khi so s\u00e1nh t\u1eeb tr\u01b0\u1eddng c\u1ee7a nam ch\u00e2m th\u1eb3ng v\u00e0 t\u1eeb tr\u01b0\u1eddng c\u1ee7a \u00f4ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua ? ","select":["A . T\u1eeb tr\u01b0\u1eddng b\u00ean trong c\u1ee7a \u1ed1ng d\u00e2y v\u00e0 t\u1eeb tr\u01b0\u1eddng c\u1ee7a nam ch\u00e2m th\u1eb3ng ho\u00e0n to\u00e0n gi\u1ed1ng nhau","B . T\u1eeb tr\u01b0\u1eddng c\u1ee7a \u1ed1ng d\u00e2y v\u00e0 t\u1eeb tr\u01b0\u1eddng c\u1ee7a nam ch\u00e2m th\u1eb3ng ho\u00e0n to\u00e0n kh\u00e1c nhau .","C . Ph\u1ea7n t\u1eeb ph\u1ed5 b\u00ean ngo\u00e0i c\u1ee7a \u1ed1ng d\u00e2y v\u00e0 b\u00ean ngo\u00e0i c\u1ee7a nam ch\u00e2m th\u1eb3ng gi\u1ed1ng nhau .","D . \u0110\u01b0\u1eddng s\u1ee9c t\u1eeb c\u1ee7a \u1ed1ng d\u00e2y l\u00e0 c\u00e1c \u0111\u01b0\u1eddng cong k\u00edn , c\u00f2n c\u1ee7a nam ch\u00e2m l\u00e0 c\u00e1c \u0111\u01b0\u1eddng th\u1eb3ng ."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":3124},{"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":" Nh\u1eadn \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y l\u00e0 kh\u00f4ng \u0111\u00fang khi n\u00f3i v\u1ec1 \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua ? ","select":["A . \u00d4ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n b\u1ecb nhi\u1ec5m t\u1eeb v\u00e0 h\u00fat \u0111\u01b0\u1ee3c c\u00e1c v\u1eadt b\u1eb1ng s\u1eaft , th\u00e9p .","B . \u1ed0ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n b\u1ecb nhi\u1ec5m t\u1eeb v\u00e0 c\u0169ng c\u00f3 c\u00e1c t\u1eeb c\u1ef1c gi\u1ed1ng nh\u01b0 m\u1ed9t nam ch\u00e2m .","C . Khi \u0111\u1ed5i chi\u1ec1u d\u00f2ng \u0111i\u1ec7n th\u00ec \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb c\u1ee7a \u1ed1ng d\u00e2y c\u0169ng \u0111\u1ed5i chi\u1ec1u .","D . T\u1eeb tr\u01b0\u1eddng c\u1ee7a \u1ed1ng d\u00e2y l\u00e0 t\u1eeb tr\u01b0\u1eddng v\u0129nh c\u1eedu ."],"hint":"","explain":"<span class='basic_left'>T\u1eeb tr\u01b0\u1eddng c\u1ee7a \u1ed1ng d\u00e2y l\u00e0 t\u1eeb tr\u01b0\u1eddng ch\u1ec9 c\u00f3 khi c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua, khi ng\u1eaft \u0111i\u1ec7n, t\u1eeb tr\u01b0\u1eddng c\u1ee7a \u1ed1ng d\u00e2y c\u0169ng m\u1ea5t. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":3125},{"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":"T\u1eeb tr\u01b0\u1eddng trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n manh nh\u1ea5t \u1edf c\u00e1c v\u1ecb tr\u00ed n\u00e0o ? ","select":["A. \u1ede hai \u0111\u1ea7u \u1ed1ng d\u00e2y.","B. \u1ede \u0111\u1ea7u \u1ed1ng d\u00e2y l\u00e0 c\u1ef1c b\u1eafc ","C. \u1ede \u0111\u1ea7u \u1ed1ng d\u00e2y l\u00e0 c\u1ef1c nam . ","D. \u1ede trong l\u00f2ng \u1ed1ng d\u00e2y . "],"hint":"","explain":"<span class='basic_left'>T\u1eeb tr\u01b0\u1eddng trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n manh nh\u1ea5t \u1edf trong l\u00f2ng \u1ed1ng d\u00e2y .<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":3126},{"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 \u0111\u01b0a m\u1ed9t \u0111\u1ea7u c\u1ee7a thanh nam ch\u00e2m th\u1eb3ng l\u1ea1i g\u1ea7n m\u1ed9t \u0111\u1ea7u c\u1ee7a \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n , c\u00f3 th\u1ec3 x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng n\u00e0o sau \u0111\u00e2y : ","select":["A. Ch\u00fang ch\u1ec9 h\u00fat nhau . ","B. Ch\u00fang ch\u1ec9 \u0111\u1ea9y nhau . ","C. Ch\u00fang h\u00fat ho\u1eb7c \u0111\u1ea9y nhau .","D. Ch\u00fang kh\u00f4ng t\u01b0\u01a1ng t\u00e1c"],"hint":"","explain":"<span class='basic_left'>V\u00ec \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua \u0111\u00f3ng vai tr\u00f2 nh\u01b0 m\u1ed9t nam ch\u00e2m.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3127},{"time":24,"part":[{"title":"","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"Nh\u1eadn \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y l\u00e0 kh\u00f4ng \u0111\u00fang : ","select":["A . \u1ed0ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n c\u00f3 t\u1eeb tr\u01b0\u1eddng t\u01b0\u01a1ng t\u1ef1 nh\u01b0 m\u1ed9t nam ch\u00e2m th\u1eb3ng .","B . Qui t\u1eafc n\u1eafm tay ph\u1ea3i c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c chi\u1ec1u c\u1ee7a d\u00f2ng \u0111i\u1ec7n trong \u1ed1ng d\u00e2y .","C . Qui t\u1eafc n\u1eafm tay ph\u1ea3i c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c chi\u1ec1u \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb c\u1ee7a nam ch\u00e2m th\u1eb3ng .","D . Qui t\u1eafc n\u1eafm tay ph\u1ea3i d\u00f9ng \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh chi\u1ec1u c\u1ee7a \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb trong \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n ."],"hint":"","explain":"<span class='basic_left'>Qui t\u1eafc n\u1eafm tay ph\u1ea3i c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c chi\u1ec1u \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb c\u1ee7a nam ch\u00e2m th\u1eb3ng v\u00e0 c\u1ea3 \u1ed1ng d\u00e2y, d\u00e2y d\u1eabn c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":3128},{"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":"\u0110\u1ed9 l\u1edbn c\u1ea3m \u1ee9ng t\u1eeb t\u1ea1i m\u1ed9t \u0111i\u1ec3m b\u00ean trong l\u00f2ng \u1ed1ng d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n \u0111i qua s\u1ebd t\u0103ng hay gi\u1ea3m bao nhi\u00eau l\u1ea7n n\u1ebfu s\u1ed1 v\u00f2ng d\u00e2y v\u00e0 chi\u1ec1u d\u00e0i \u1ed1ng d\u00e2y \u0111\u1ec1u t\u0103ng l\u00ean hai l\u1ea7n v\u00e0 c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua \u1ed1ng d\u00e2y gi\u1ea3m b\u1ed1n l\u1ea7n.","select":["A. kh\u00f4ng \u0111\u1ed5i","B. gi\u1ea3m 2 l\u1ea7n","C. gi\u1ea3m 4 l\u1ea7n ","D. t\u0103ng 2 l\u1ea7n"],"hint":"","explain":"<span class='basic_left'>C\u1ea3m \u1ee9ng t\u1eeb trong l\u00f2ng \u1ed1ng d\u00e2y: <br\/> $B=4\\pi \\times {{10}^{-7}}\\times n\\times I$ $(n=\\dfrac{N}{l})$ <br\/>Khi N' = 2N; l' = 2l; ${{I}^{'}}=\\dfrac{I}{4}$ th\u00ec ${{B}^{'}}=\\dfrac{B}{4}$ <br\/>\u21d2 B gi\u1ea3m 4 l\u1ea7n.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3129},{"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":"Ng\u01b0\u1eddi ta mu\u1ed1n t\u1ea1o ra t\u1eeb tr\u01b0\u1eddng c\u00f3 c\u1ea3m \u1ee9ng t\u1eeb $B\\text{ }=\\text{ }250\\times {{10}^{-5}}$ T b\u00ean trong m\u1ed9t \u1ed1ng d\u00e2y, m\u00e0 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y trong m\u1ed7i v\u00f2ng c\u1ee7a \u1ed1ng d\u00e2y ch\u1ec9 l\u00e0 2A th\u00ec s\u1ed1 v\u00f2ng qu\u1ea5n tr\u00ean \u1ed1ng ph\u1ea3i l\u00e0 bao nhi\u00eau, bi\u1ebft \u1ed1ng d\u00e2y d\u00e0i 50cm. ","select":["A. 7490 v\u00f2ng","B. 4790 v\u00f2ng","C. 479 v\u00f2ng","D. 497 v\u00f2ng"],"hint":"","explain":"<span class='basic_left'>C\u1ea3m \u1ee9ng t\u1eeb trong l\u00f2ng \u1ed1ng d\u00e2y: <br\/>$B=4\\pi \\times {{10}^{-7}}\\times n\\times I=4\\pi \\times {{10}^{-7}}\\times \\dfrac{N}{l}\\times I$. <br\/>$\\Rightarrow N=\\dfrac{B\\times l}{4\\pi \\times {{10}^{-7}}\\times I}=\\dfrac{250\\times {{10}^{-5}}\\times 0,5}{4\\pi \\times {{10}^{-7}}\\times 2}=497$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":3130}],"lesson":{"save":0,"level":2}}