{"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":"M\u1ed9t \u0111o\u1ea1n d\u00e2y d\u1eabn b\u1eb1ng \u0111\u1ed3ng d\u00e0i $l_{1}^{{}}$=10m c\u00f3 \u0111i\u1ec7n tr\u1edf $R_{1}^{{}}$ v\u00e0 m\u1ed9t d\u00e2y d\u1eabn b\u1eb1ng nh\u00f4m d\u00e0i $l_{2}^{{}}$=5m c\u00f3 \u0111i\u1ec7n tr\u1edf $R_{2}^{{}}$. C\u00e2u tr\u1ea3 l\u1eddi n\u00e0o d\u01b0\u1edbi \u0111\u00e2y l\u00e0 \u0111\u00fang khi so s\u00e1nh $R_{1}^{{}}$v\u00e0 $R_{2}^{{}}$?","select":["A. $R_{1}^{{}}$=2$R_{2}^{{}}$","B. $R_{1}^{{}}$<2$R_{2}^{{}}$","C. $R_{1}^{{}}$>2$R_{2}^{{}}$","D. Kh\u00f4ng \u0111\u1ee7 \u0111i\u1ec1u ki\u1ec7n \u0111\u1ec3 so s\u00e1nh $R_{1}^{{}}$ v\u1edbi $R_{2}^{{}}$."],"hint":"","explain":"<span class='basic_left'>V\u00ec ch\u01b0a bi\u1ebft ti\u1ebft di\u1ec7n c\u1ee7a d\u00e2y n\u00ean ta ch\u01b0a th\u1ec3 so s\u00e1nh \u0111i\u1ec7n tr\u1edf c\u1ee7a hai \u0111o\u1ea1n d\u00e2y n\u00e0y. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":2931},{"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":"\u0110i\u1ec7n tr\u1edf c\u1ee7a d\u00e2y d\u1eabn kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o y\u1ebfu t\u1ed1 n\u00e0o d\u01b0\u1edbi \u0111\u00e2y?","select":["A. V\u1eadt li\u1ec7u l\u00e0m d\u00e2y d\u1eabn.","B. Kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a d\u00e2y d\u1eabn.","C. Chi\u1ec1u d\u00e0i c\u1ee7a d\u00e2y d\u1eabn.","D. Ti\u1ebft di\u1ec7n c\u1ee7a d\u00e2y d\u1eabn."],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf c\u1ee7a d\u00e2y d\u1eabn kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a d\u00e2y d\u1eabn.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2932},{"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\u1ec3 t\u00ecm hi\u1ec3u s\u1ef1 ph\u1ee5 thu\u1ed9c c\u1ee7a \u0111i\u1ec7n tr\u1edf d\u00e2y d\u1eabn v\u00e0o chi\u1ec1u d\u00e0i d\u00e2y d\u1eabn, c\u1ea7n ph\u1ea3i x\u00e1c \u0111\u1ecbnh v\u00e0 so s\u00e1nh \u0111i\u1ec7n tr\u1edf c\u1ee7a c\u00e1c d\u00e2y d\u1eabn c\u00f3 nh\u1eefng \u0111\u1eb7c \u0111i\u1ec3m n\u00e0o?","select":["A. C\u00e1c d\u00e2y d\u1eabn n\u00e0y ph\u1ea3i c\u00f3 c\u00f9ng ti\u1ebft di\u1ec7n, \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb c\u00f9ng m\u1ed9t v\u1eadt li\u1ec7u, nh\u01b0ng c\u00f3 chi\u1ec1u d\u00e0i kh\u00e1c nhau.","B. C\u00e1c d\u00e2y d\u1eabn n\u00e0y ph\u1ea3i c\u00f3 c\u00f9ng chi\u1ec1u d\u00e0i, \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb c\u00f9ng m\u1ed9t v\u1eadt li\u1ec7u, nh\u01b0ng c\u00f3 ti\u1ebft di\u1ec7n kh\u00e1c nhau.","C. C\u00e1c d\u00e2y d\u1eabn n\u00e0y ph\u1ea3i c\u00f3 c\u00f9ng chi\u1ec1u d\u00e0i, c\u00f9ng ti\u1ebft di\u1ec7n, nh\u01b0ng \u0111\u01b0\u1ee3c l\u00e0m b\u1eb1ng c\u00e1c v\u1eadt li\u1ec7u kh\u00e1c nhau.","D. C\u00e1c d\u00e2y d\u1eabn n\u00e0y ph\u1ea3i \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb c\u00f9ng m\u1ed9t v\u1eadt li\u1ec7u, nh\u01b0ng c\u00f3 chi\u1ec1u d\u00e0i v\u00e0 ti\u1ebft di\u1ec7n kh\u00e1c nhau."],"hint":"","explain":"<span class='basic_left'>\u0110\u1ec3 t\u00ecm hi\u1ec3u s\u1ef1 ph\u1ee5 thu\u1ed9c c\u1ee7a \u0111i\u1ec7n tr\u1edf d\u00e2y d\u1eabn v\u00e0o chi\u1ec1u d\u00e0i d\u00e2y d\u1eabn, c\u1ea7n ph\u1ea3i x\u00e1c \u0111\u1ecbnh v\u00e0 so s\u00e1nh \u0111i\u1ec7n tr\u1edf c\u1ee7a c\u00e1c d\u00e2y d\u1eabn c\u00f3 c\u00f9ng ti\u1ebft di\u1ec7n, \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb c\u00f9ng m\u1ed9t v\u1eadt li\u1ec7u, nh\u01b0ng c\u00f3 chi\u1ec1u d\u00e0i kh\u00e1c nhau. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":2933},{"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":"Hai d\u00e2y d\u1eabn b\u1eb1ng nh\u00f4m c\u00f3 c\u00f9ng ti\u1ebft di\u1ec7n, m\u1ed9t d\u00e2y d\u00e0i 2m c\u00f3 \u0111i\u1ec7n tr\u1edf $R_{1}^{{}}$ v\u00e0 d\u00e2y kia d\u00e0i 6m c\u00f3 \u0111i\u1ec7n tr\u1edf $R_{2}^{{}}$. T\u00ednh t\u1ec9 s\u1ed1 $\\dfrac{R_{1}^{{}}}{R_{2}^{{}}}$.","select":["A. 6","B. 3","C. 2","D. $\\dfrac{1}{3}$"],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3: $\\dfrac{R_{1}^{{}}}{R_{2}^{{}}}=\\dfrac{l_{1}}{l_{2}}=\\dfrac{2}{6}=\\dfrac{1}{3}$ <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":2934},{"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 d\u00e2y d\u1eabn d\u00e0i 120m \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ebf qu\u1ea5n th\u00e0nh m\u1ed9t cu\u1ed9n d\u00e2y. Khi \u0111\u1eb7t hi\u1ec7u \u0111i\u1ec7n th\u1ebf 30V v\u00e0o hai \u0111\u1ea7u cu\u1ed9n d\u00e2y n\u00e0y th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua n\u00f3 l\u00e0 125mA.T\u00ednh \u0111i\u1ec7n tr\u1edf c\u1ee7a cu\u1ed9n d\u00e2y.","select":["A. 240\u03a9","B. 120\u03a9","C. 480\u03a9","D. 60\u03a9"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf c\u1ee7a cu\u1ed9n d\u00e2y: $R=\\dfrac{U}{I}=\\dfrac{30}{0,125}=240\\Omega $<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2935},{"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":"M\u1ed9t d\u00e2y d\u1eabn d\u00e0i 120m \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ebf qu\u1ea5n th\u00e0nh m\u1ed9t cu\u1ed9n d\u00e2y. Khi \u0111\u1eb7t hi\u1ec7u \u0111i\u1ec7n th\u1ebf 30V v\u00e0o hai \u0111\u1ea7u cu\u1ed9n d\u00e2y n\u00e0y th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua n\u00f3 l\u00e0 125mA. M\u1ed7i \u0111o\u1ea1n d\u00e0i 1m c\u1ee7a d\u00e2y d\u1eabn n\u00e0y c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 bao nhi\u00eau?","select":["A. 3\u03a9","B. 4\u03a9","C. 2\u03a9","D. 1\u03a9"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf c\u1ee7a cu\u1ed9n d\u00e2y: $R=\\dfrac{U}{I}=\\dfrac{30}{0,125}=240\\Omega $<br\/>\u0110i\u1ec7n tr\u1edf c\u1ee7a m\u1ed7i \u0111o\u1ea1n 1m c\u1ee7a d\u00e2y d\u1eabn n\u00e0y: $r=\\dfrac{R}{l}=\\dfrac{240}{120}=2\\Omega $<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2936},{"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":"D\u00e2y t\u00f3c c\u1ee7a m\u1ed9t b\u00f3ng \u0111\u00e8n khi ch\u01b0a m\u1eafc v\u00e0o m\u1ea1ch c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 24\u2126. M\u1ed7i \u0111o\u1ea1n d\u00e0i 1cm c\u1ee7a d\u00e2y t\u00f3c n\u00e0y c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 1,5\u2126. T\u00ednh chi\u1ec1u d\u00e0i c\u1ee7a to\u00e0n b\u1ed9 s\u1ee3i d\u00e2y t\u00f3c c\u1ee7a b\u00f3ng \u0111\u00e8n \u0111\u00f3.","select":["A. 24cm","B. 12cm","C. 16cm","D. 10cm"],"hint":"","explain":"<span class='basic_left'>Chi\u1ec1u d\u00e0i c\u1ee7a to\u00e0n b\u1ed9 s\u1ee3i d\u00e2y t\u00f3c: $l=\\dfrac{24}{1,5}=16cm$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2937},{"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":"\u0110\u01b0\u1eddng d\u00e2y d\u1eabn c\u1ee7a m\u1ed9t m\u1ea1ng \u0111i\u1ec7n trong gia \u0111\u00ecnh n\u1ebfu n\u1ed1i d\u00e0i li\u00ean ti\u1ebfp v\u1edbi nhau s\u1ebd c\u00f3 chi\u1ec1u d\u00e0i t\u1ed5ng c\u1ed9ng l\u00e0 500m v\u00e0 \u0111i\u1ec7n tr\u1edf c\u1ee7a m\u1ed7i \u0111o\u1ea1n c\u00f3 chi\u1ec1u d\u00e0i 1m c\u1ee7a \u0111\u01b0\u1eddng d\u00e2y n\u00e0y c\u00f3 \u0111i\u1ec7n tr\u1edf trung b\u00ecnh l\u00e0 0,02\u2126. T\u00ednh \u0111i\u1ec7n tr\u1edf t\u1ed5ng c\u1ed9ng c\u1ee7a to\u00e0n b\u1ed9 \u0111\u01b0\u1eddng d\u00e2y d\u1eabn n\u1ed1i d\u00e0i li\u00ean ti\u1ebfp n\u00e0y.","select":["A. 5\u03a9","B. 10\u03a9","C. 8\u03a9","D. 12\u03a9"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf t\u1ed5ng c\u1ed9ng c\u1ee7a to\u00e0n b\u1ed9 \u0111\u01b0\u1eddng d\u00e2y d\u1eabn n\u1ed1i d\u00e0i li\u00ean ti\u1ebfp n\u00e0y: $R=\\dfrac{0,02\\times 500}{1}=10\\Omega $ <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2938},{"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":"\u0110o\u1ea1n d\u00e2y d\u1eabn n\u1ed1i t\u1eeb c\u1ed9t \u0111i\u1ec7n v\u00e0o m\u1ed9t gia \u0111\u00ecnh c\u00f3 chi\u1ec1u d\u00e0i t\u1ed5ng c\u1ed9ng l\u00e0 50m v\u00e0 c\u00f3 \u0111i\u1ec7n tr\u1edf t\u1ed5ng c\u1ed9ng l\u00e0 0,5\u2126. H\u1ecfi m\u1ed7i \u0111o\u1ea1n d\u00e0i 1m c\u1ee7a d\u00e2y n\u00e0y c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 bao nhi\u00eau?","select":["A. 0,01\u03a9","B. 0,1\u03a9","C. 0,05\u03a9","D. 0,15\u03a9"],"hint":"","explain":"<span class='basic_left'>M\u1ed7i \u0111o\u1ea1n d\u00e0i 1m c\u1ee7a d\u00e2y n\u00e0y c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0: $R=\\dfrac{0,5\\times 1}{50}=0,01\\Omega $<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2939},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/vatly/bai7/lv2/img\/h10.jpg'\/><\/center>H\u00ecnh v\u1ebd bi\u1ec3u di\u1ec5n m\u1ed9t \u0111o\u1ea1n d\u00e2y d\u1eabn AB \u0111\u1ed3ng ch\u1ea5t, ti\u1ebft di\u1ec7n \u0111\u1ec1u, hai \u0111i\u1ec3m M v\u00e0 N chia d\u00e2y d\u1eabn AB th\u00e0nh ba \u0111o\u1ea1n d\u00e0i b\u1eb1ng nhau: AM = MN = NB. Cho d\u00f2ng \u0111i\u1ec7n c\u01b0\u1eddng \u0111\u1ed9 I ch\u1ea1y qua d\u00e2y d\u1eabn n\u00e0y. H\u00e3y cho bi\u1ebft hi\u1ec7u \u0111i\u1ec7n th\u1ebf $U_{AB}^{{}}$ b\u1eb1ng bao nhi\u00eau l\u1ea7n hi\u1ec7u \u0111i\u1ec7n th\u1ebf $U_{MN}^{{}}$.","select":["A. 1","B. 2","C. 3","D. 4"],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3: $U_{AB}^{{}}=\\text{I}\\times \\text{R}_{AB}^{{}}=\\text{I}\\times \\text{R}_{MN}^{{}}\\times \\dfrac{l_{AB}^{{}}}{l_{MB}^{{}}}=\\text{I}\\times \\text{R}_{MN}^{{}}\\times 3=3U_{MN}^{{}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2940},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/vatly/bai7/lv2/img\/h10.jpg'\/><\/center>H\u00ecnh v\u1ebd bi\u1ec3u di\u1ec5n m\u1ed9t \u0111o\u1ea1n d\u00e2y d\u1eabn AB \u0111\u1ed3ng ch\u1ea5t, ti\u1ebft di\u1ec7n \u0111\u1ec1u, hai \u0111i\u1ec3m M v\u00e0 N chia d\u00e2y d\u1eabn AB th\u00e0nh ba \u0111o\u1ea1n d\u00e0i b\u1eb1ng nhau: AM = MN = NB. Cho d\u00f2ng \u0111i\u1ec7n c\u01b0\u1eddng \u0111\u1ed9 I ch\u1ea1y qua d\u00e2y d\u1eabn n\u00e0y. H\u00e3y cho bi\u1ebft hi\u1ec7u \u0111i\u1ec7n th\u1ebf $U_{AN}^{{}}$ b\u1eb1ng bao nhi\u00eau l\u1ea7n hi\u1ec7u \u0111i\u1ec7n th\u1ebf $U_{MB}^{{}}$.","select":["A. 1","B. 2","C. 3","D. 4"],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3: $U_{AN}^{{}}=\\text{I}\\times \\text{R}_{AN}^{{}}=\\text{I}\\times \\text{R}_{MB}^{{}}\\times \\dfrac{l_{AN}^{{}}}{l_{MB}^{{}}}=\\text{I}\\times \\text{R}_{MB}^{{}}=U_{MB}^{{}}$ <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2941},{"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 qu\u1ea5n m\u1ed9t d\u00e2y d\u1eabn \u0111i\u1ec7n tr\u1edf quanh m\u1ed9t l\u00f5i s\u1ee9 h\u00ecnh tr\u1ee5 tr\u00f2n v\u1edbi \u0111\u01b0\u1eddng k\u00ednh l\u00f5i s\u1ee9 l\u00e0 1,5cm. Bi\u1ebft 1m d\u00e2y qu\u1ea5n c\u00f3 \u0111i\u1ec7n tr\u1edf 2\u03a9. H\u1ecfi cu\u1ed9n n\u00e0y g\u1ed3m bao nhi\u00eau v\u00f2ng d\u00e2y n\u1ebfu \u0111i\u1ec7n tr\u1edf c\u1ee7a c\u1ea3 cu\u1ed9n d\u00e2y l\u00e0 30\u03a9? Bi\u1ebft r\u1eb1ng c\u00e1c v\u00f2ng d\u00e2y \u0111\u01b0\u1ee3c cu\u1ed1n s\u00e1t nhau th\u00e0nh m\u1ed9t l\u1edbp.","select":["A. 181,5","B. 218,5","C. 381,5","D. 318,5"],"hint":"","explain":"<span class='basic_left'>C\u1ee9 1 m d\u00e2y d\u1eabn c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 2 \u03a9<br\/>xm d\u00e2y d\u1eabn c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 30 \u03a9<br\/>$\\Rightarrow x=\\dfrac{30\\times 1}{2}=15m$<br\/>Chu vi c\u1ee7a v\u00f2ng 1 qu\u1ea5n d\u00e2y: $c=3,14\\times d=3,14\\times 1,5\\times {{10}^{-2}}=0,0471m$<br\/>S\u1ed1 v\u00f2ng c\u1ee7a cu\u1ed9n d\u00e2y n\u00e0y l\u00e0: $n=\\dfrac{15}{0,0471}\\approx 318,5$ (v\u00f2ng)<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":2942},{"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":"C\u00f3 tr\u01b0\u1eddng h\u1ee3p b\u1ebfp \u0111i\u1ec7n s\u1eed d\u1ee5ng d\u00e2y nung l\u00e0 d\u00e2y mayso b\u1ecb \u0111\u1ee9t, ta c\u00f3 th\u1ec3 n\u1ed1i ch\u1ed7 d\u00e2y \u0111\u1ee9t l\u1ea1i \u0111\u1ec3 ti\u1ebfp t\u1ee5c s\u1eed d\u1ee5ng. H\u1ecfi khi \u0111\u00f3 \u0111i\u1ec7n tr\u1edf c\u1ee7a d\u00e2y nung n\u00e0y thay \u0111\u1ed5i nh\u01b0 th\u1ebf n\u00e0o so v\u1edbi tr\u01b0\u1edbc? Bi\u1ebft r\u1eb1ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u0111\u1eb7t v\u00e0o hai \u0111\u1ea7u d\u00e2y v\u1eabn nh\u01b0 tr\u01b0\u1edbc.","select":["A. Nh\u1ecf h\u01a1n","B. L\u1edbn h\u01a1n","C. B\u1eb1ng nhau","D. Kh\u00f4ng so s\u00e1nh \u0111\u01b0\u1ee3c"],"hint":"","explain":"<span class='basic_left'>Khi c\u00f3 \u0111i\u1ec7n tr\u1edf c\u1ee7a d\u00e2y nung n\u00e0y s\u1ebd nh\u1ecf h\u01a1n. V\u00ec khi b\u1ecb \u0111\u1ee9t v\u00e0 sau khi n\u1ed1i l\u1ea1i th\u00ec d\u00e2y nung s\u1ebd ng\u1eafn h\u01a1n n\u00ean \u0111i\u1ec7n tr\u1edf c\u1ee7a d\u00e2y nung s\u1ebd nh\u1ecf h\u01a1n tr\u01b0\u1edbc. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2943},{"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 d\u00e2y d\u1eabn d\u00e0i 80m \u0111\u01b0\u1ee3c u\u1ed1n th\u00e0nh m\u1ed9t cu\u1ed9n d\u00e2y. Khi \u0111\u1eb7t m\u1ed9t hi\u1ec7u \u0111i\u1ec7n th\u1ebf 40V v\u00e0o hai \u0111\u1ea7u cu\u1ed9n d\u00e2y n\u00e0y th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua n\u00f3 l\u00e0 250mA. M\u1ed7i \u0111o\u1ea1n d\u00e2y d\u00e0i 1m s\u1ebd c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0:","select":["A. 1\u03a9","B. 2\u03a9","C. 3\u03a9","D. 4\u03a9"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf cu\u1ed9n d\u00e2y: $R=\\dfrac{U}{I}=\\dfrac{40}{0,25}=160\\Omega $<br\/>\u0110i\u1ec7n tr\u1edf m\u1ed7i \u0111o\u1ea1n d\u00e2y d\u00e0i 1m: $r=\\dfrac{160}{80}=2\\Omega $<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2944},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":"M\u1ed9t d\u00e2y \u0111i\u1ec7n tr\u1edf c\u00f3 chi\u1ec1u d\u00e0i 12m v\u00e0 c\u00f3 \u0111i\u1ec7n tr\u1edf 36\u03a9. \u0110i\u1ec7n tr\u1edf d\u00e2y d\u1eabn khi c\u1eaft ng\u1eafn d\u00e2y \u0111i 2m l\u00e0:","select":["A. 10\u03a9.","B. 20\u03a9.","C. 30\u03a9.","D. 40\u03a9."],"hint":"","explain":"<span class='basic_left'>C\u1eaft ng\u1eafn d\u00e2y \u0111i 2m th\u00ec 10m d\u00e2y c\u00f2n l\u1ea1i c\u00f3 \u0111i\u1ec7n tr\u1edf:$R=\\dfrac{36\\times 10}{12}=30\\Omega $ <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2945},{"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":"Hai d\u00e2y d\u1eabn b\u1eb1ng \u0111\u1ed3ng c\u00f3 c\u00f9ng ti\u1ebft di\u1ec7n, m\u1ed9t d\u00e2y c\u00f3 chi\u1ec1u d\u00e0i $l_{1}^{{}}$v\u00e0 \u0111i\u1ec7n tr\u1edf 4\u03a9, d\u00e2y kia c\u00f3 chi\u1ec1u d\u00e0i $l_{2}^{{}}$ v\u00e0 \u0111i\u1ec7n tr\u1edf 12\u03a9. T\u1ec9 s\u1ed1 $\\dfrac{l_{1}^{{}}}{l_{2}^{{}}}$b\u1eb1ng:","select":["A. $\\dfrac{1}{2}$","B. 2 ","C. $\\dfrac{1}{3}$","D. 3"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi chi\u1ec1u d\u00e0i d\u00e2y n\u00ean:<br\/>$\\dfrac{l_{1}^{{}}}{l_{2}^{{}}}=\\dfrac{R_{1}^{{}}}{R_{2}^{{}}}=\\dfrac{4}{12}=\\dfrac{1}{3}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2946},{"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\u1eb7t hi\u1ec7u \u0111i\u1ec7n th\u1ebf 6V v\u00e0o hai \u0111\u1ea7u m\u1ed9t cu\u1ed9n d\u00e2y th\u00ec d\u00f2ng \u0111i\u1ec7n qua n\u00f3 c\u00f3 c\u01b0\u1eddng \u0111\u1ed9 l\u00e0 0,3A. Bi\u1ebft r\u1eb1ng d\u00e2y d\u1eabn lo\u1ea1i n\u00e0y n\u1ebfu d\u00e0i 4m th\u00ec c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 2\u03a9. V\u1eady chi\u1ec1u d\u00e0i c\u1ee7a d\u00e2y d\u1eabn d\u00f9ng \u0111\u1ec3 cu\u1ed1n cu\u1ed9n d\u00e2y n\u00e0y l\u00e0 bao nhi\u00eau?","select":["A. 20m","B. 30m","C. 40m","D. 50m"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf d\u00e2y: $R=\\dfrac{U}{I}=\\dfrac{6}{0,3}=20\\Omega $<br\/>Chi\u1ec1u d\u00e0i d\u00e2y: $l=\\dfrac{20\\times 4}{2}=40m$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2947},{"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":"Hai d\u00e2y d\u1eabn b\u1eb1ng \u0111\u1ed3ng, c\u00f3 c\u00f9ng ti\u1ebft di\u1ec7n, d\u00e2y th\u1ee9 nh\u1ea5t c\u00f3 \u0111i\u1ec7n tr\u1edf l\u00e0 2\u03a9 v\u00e0 c\u00f3 chi\u1ec1u d\u00e0i 10m, d\u00e2y th\u1ee9 hai c\u00f3 chi\u1ec1u d\u00e0i 30m. \u0110i\u1ec7n tr\u1edf c\u1ee7a d\u00e2y th\u1ee9 hai l\u00e0 bao nhi\u00eau?","select":["A. 4\u03a9","B. 6\u03a9","C. 8\u03a9","D. 10\u03a9"],"hint":"","explain":"<span class='basic_left'>Do \u0111i\u1ec7n tr\u1edf t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi chi\u1ec1u d\u00e0i d\u00e2y n\u00ean: $R=\\dfrac{2\\times 30}{10}=6\\Omega $<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":2948},{"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":"Ba d\u00e2y d\u1eabn c\u00f3 c\u00f9ng ti\u1ebft di\u1ec7n, c\u00f9ng l\u00e0m b\u1eb1ng \u0111\u1ed3ng. D\u00e2y th\u1ee9 nh\u1ea5t d\u00e0i 4m c\u00f3 \u0111i\u1ec7n tr\u1edf $R_{1}^{{}}$, d\u00e2y th\u1ee9 hai d\u00e0i 6m c\u00f3 \u0111i\u1ec7n tr\u1edf $R_{2}^{{}}$, d\u00e2y th\u1ee9 ba d\u00e0i 10m c\u00f3 \u0111i\u1ec7n tr\u1edf $R_{3}^{{}}$. C\u00e2u tr\u1ea3 l\u1eddi n\u00e0o d\u01b0\u1edbi \u0111\u00e2y l\u00e0 \u0111\u00fang khi so s\u00e1nh \u0111i\u1ec7n tr\u1edf c\u1ee7a c\u00e1c d\u00e2y d\u1eabn?","select":["A. $R_{3}^{{}}$ > $R_{2}^{{}}$ > $R_{1}^{{}}$","B. $R_{1}^{{}}$ > $R_{3}^{{}}$ > $R_{2}^{{}}$","C. $R_{2}^{{}}$ > $R_{1}^{{}}$> $R_{3}^{{}}$","D. $R_{1}^{{}}$ > $R_{2}^{{}}$ > $R_{3}^{{}}$"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf c\u1ee7a c\u00e1c d\u00e2y d\u1eabn c\u00f3 c\u00f9ng ti\u1ebft di\u1ec7n v\u00e0 \u0111\u01b0\u1ee3c l\u00e0m t\u1eeb c\u00f9ng m\u1ed9t lo\u1ea1i v\u1eadt li\u1ec7u th\u00ec t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi chi\u1ec1u d\u00e0i c\u1ee7a m\u1ed7i d\u00e2y.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":2949},{"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":"Hai d\u00e2y nh\u00f4m c\u00f9ng ti\u1ebft di\u1ec7n c\u00f3 \u0111i\u1ec7n tr\u1edf l\u1ea7n l\u01b0\u1ee3t l\u00e0 5\u03a9 v\u00e0 6\u03a9. D\u00e2y th\u1ee9 nh\u1ea5t d\u00e0i 15m. Chi\u1ec1u d\u00e0i c\u1ee7a d\u00e2y th\u1ee9 hai l\u00e0 bao nhi\u00eau?","select":["A. 16m","B. 17m","C. 18m","D. 20m"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tr\u1edf t\u1ec9 l\u1ec7 v\u1edbi chi\u1ec1u d\u00e0i n\u00ean: $R=\\dfrac{6\\times 15}{5}=18m$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":2950}],"lesson":{"save":0,"level":2}}