{"segment":[{"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 chuy\u1ec3n \u0111i\u1ec7n \u00e1p t\u1eeb \u0111\u01b0\u1eddng d\u00e2y cao th\u1ebf xu\u1ed1ng \u0111i\u1ec7n \u00e1p s\u1eed d\u1ee5ng th\u00ec c\u1ea7n d\u00f9ng ","select":["A. bi\u1ebfn th\u1ebf t\u0103ng \u0111i\u1ec7n \u00e1p.","B. bi\u1ebfn th\u1ebf gi\u1ea3m \u0111i\u1ec7n \u00e1p.","C. bi\u1ebfn th\u1ebf \u1ed5n \u00e1p.","D. c\u1ea3 bi\u1ebfn th\u1ebf t\u0103ng \u00e1p v\u00e0 bi\u1ebfn th\u1ebf h\u1ea1 \u00e1p."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3331},{"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":"C\u00f4ng su\u1ea5t hao ph\u00ed do t\u1ecfa nhi\u1ec7t tr\u00ean \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n ","select":["A. t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u0111\u1eb7t v\u00e0o hai \u0111\u1ea7u d\u00e2y.","B. t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u0111\u1eb7t v\u00e0o hai \u0111\u1ea7u d\u00e2y.","C. t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi b\u00ecnh ph\u01b0\u01a1ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u0111\u1eb7t v\u00e0o hai \u0111\u1ea7u d\u00e2y.","D. t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi b\u00ecnh ph\u01b0\u01a1ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u0111\u1eb7t v\u00e0o hai \u0111\u1ea7u d\u00e2y."],"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":3332},{"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":"Tr\u00ean \u0111\u01b0\u1eddng d\u00e2y truy\u1ec1n t\u1ea3i \u0111i\u1ec7n B\u1eafc Nam 500kV, ng\u01b0\u1eddi ta th\u01b0\u1eddng d\u00f9ng d\u00e2y d\u1eabn b\u1eb1ng ch\u1ea5t li\u1ec7u g\u00ec?","select":["A. Nh\u00f4m","B. S\u1eaft","C. \u0110\u1ed3ng","D. Th\u00e9p"],"hint":"","explain":"<span class='basic_left'> V\u00ec Nh\u00f4m d\u1eabn \u0111i\u1ec7n t\u1ed1t, kh\u00f4ng b\u1ecb oxy h\u00f3a (han r\u1ec9), nh\u1eb9 v\u00e0 gi\u00e1 th\u00e0nh kh\u00f4ng qu\u00e1 \u0111\u1eaft.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3333},{"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":" Khi truy\u1ec1n t\u1ea3i \u0111i\u1ec7n n\u0103ng t\u1eeb n\u01a1i s\u1ea3n xu\u1ea5t \u0111\u1ebfn n\u01a1i ti\u00eau th\u1ee5, \u0111\u1ec3 l\u00e0m gi\u1ea3m hao ph\u00ed tr\u00ean \u0111\u01b0\u1eddng d\u00e2y do t\u1ecfa nhi\u1ec7t ta c\u00f3 th\u1ec3 ","select":["A. \u0111\u1eb7t \u1edf \u0111\u1ea7u ra c\u1ee7a nh\u00e0 m\u00e1y \u0111i\u1ec7n m\u00e1y t\u0103ng th\u1ebf.","B. \u0111\u1eb7t \u1edf \u0111\u1ea7u ra c\u1ee7a nh\u00e0 m\u00e1y \u0111i\u1ec7n m\u00e1y h\u1ea1 th\u1ebf.","C. \u0111\u1eb7t \u1edf n\u01a1i ti\u00eau th\u1ee5 m\u00e1y h\u1ea1 th\u1ebf.","D. \u0111\u1eb7t \u1edf \u0111\u1ea7u ra c\u1ee7a nh\u00e0 m\u00e1y \u0111i\u1ec7n m\u00e1y t\u0103ng th\u1ebf v\u00e0 \u0111\u1eb7t \u1edf n\u01a1i ti\u00eau th\u1ee5 m\u00e1y h\u1ea1 th\u1ebf."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":3334},{"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":"N\u1ebfu hi\u1ec7u \u0111i\u1ec7n th\u1ebf gi\u1eefa hai \u0111\u1ea7u \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n kh\u00f4ng \u0111\u1ed5i m\u00e0 d\u00e2y d\u1eabn c\u00f3 chi\u1ec1u d\u00e0i t\u0103ng g\u1ea5p \u0111\u00f4i th\u00ec hao ph\u00ed do t\u1ecfa nhi\u1ec7t tr\u00ean \u0111\u01b0\u1eddng d\u00e2y s\u1ebd ","select":["A. t\u0103ng l\u00ean g\u1ea5p \u0111\u00f4i.","B. gi\u1ea3m \u0111i m\u1ed9t n\u1eeda.","C. t\u0103ng l\u00ean g\u1ea5p b\u1ed1n.","D. gi\u1eef nguy\u00ean kh\u00f4ng \u0111\u1ed5i."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3335},{"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 t\u0103ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf hai \u0111\u1ea7u d\u00e2y d\u1eabn tr\u00ean \u0111\u01b0\u1eddng d\u00e2y truy\u1ec1n t\u1ea3i \u0111i\u1ec7n l\u00ean g\u1ea5p \u0111\u00f4i th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed tr\u00ean \u0111\u01b0\u1eddng d\u00e2y s\u1ebd ","select":["A. gi\u1ea3m \u0111i m\u1ed9t n\u1eeda.","B. gi\u1ea3m \u0111i b\u1ed1n l\u1ea7n","C. t\u0103ng l\u00ean g\u1ea5p \u0111\u00f4i.","D. t\u0103ng l\u00ean g\u1ea5p b\u1ed1n."],"hint":"","explain":"<span class='basic_left'>$P=U\\times I={{I}^{2}}\\times R={{\\frac{U}{R}}^{2}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3336},{"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":"Tr\u00ean c\u00f9ng m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n, n\u1ebfu t\u0103ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u1edf hai \u0111\u1ea7u d\u00e2y d\u1eabn l\u00ean 100 l\u1ea7n th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed do t\u1ecfa nhi\u1ec7t tr\u00ean \u0111\u01b0\u1eddng d\u00e2y s\u1ebd ","select":["A. t\u0103ng 102 l\u1ea7n.","B. gi\u1ea3m 102 l\u1ea7n.","C. t\u0103ng 104 l\u1ea7n.","D. gi\u1ea3m 104 l\u1ea7n."],"hint":"","explain":"<span class='basic_left'>$P=U\\times I={{I}^{2}}\\times R={{\\frac{U}{R}}^{2}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":3337},{"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":"C\u00f9ng c\u00f4ng su\u1ea5t \u0111i\u1ec7n P \u0111\u01b0\u1ee3c t\u1ea3i \u0111i tr\u00ean c\u00f9ng m\u1ed9t d\u00e2y d\u1eabn. C\u00f4ng su\u1ea5t hao ph\u00ed khi hi\u1ec7u \u0111i\u1ec7n th\u1ebf hai \u0111\u1ea7u \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n l\u00e0 400kV so v\u1edbi khi hi\u1ec7u \u0111i\u1ec7n th\u1ebf l\u00e0 200kV l\u00e0 ","select":["A. l\u1edbn h\u01a1n 2 l\u1ea7n.","B. nh\u1ecf h\u01a1n 2 l\u1ea7n.","C. nh\u1ecf h\u01a1n 4 l\u1ea7n.","D. l\u1edbn h\u01a1n 4 l\u1ea7n."],"hint":"","explain":"<span class='basic_left'>$P=U\\times I={{I}^{2}}\\times R={{\\frac{U}{R}}^{2}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3338},{"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 truy\u1ec1n \u0111i c\u00f9ng m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n, ng\u01b0\u1eddi ta d\u00f9ng d\u00e2y d\u1eabn c\u00f9ng ch\u1ea5t nh\u01b0ng c\u00f3 ti\u1ebft di\u1ec7n g\u1ea5p \u0111\u00f4i d\u00e2y ban \u0111\u1ea7u. C\u00f4ng su\u1ea5t hao ph\u00ed tr\u00ean \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n so v\u1edbi l\u00fac \u0111\u1ea7u ","select":["A. kh\u00f4ng thay \u0111\u1ed5i.","B. gi\u1ea3m \u0111i hai l\u1ea7n.","C. gi\u1ea3m \u0111i b\u1ed1n l\u1ea7n.","D. t\u0103ng l\u00ean hai l\u1ea7n."],"hint":"","explain":"<span class='basic_left'>$P=U\\times I={{I}^{2}}\\times R={{\\frac{U}{R}}^{2}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3339},{"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":" Tr\u00ean m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y truy\u1ec1n t\u1ea3i \u0111i\u1ec7n c\u00f3 c\u00f4ng su\u1ea5t truy\u1ec1n t\u1ea3i kh\u00f4ng \u0111\u1ed5i, n\u1ebfu t\u0103ng ti\u1ebft di\u1ec7n d\u00e2y d\u1eabn l\u00ean g\u1ea5p \u0111\u00f4i, \u0111\u1ed3ng th\u1eddi c\u0169ng t\u0103ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf truy\u1ec1n t\u1ea3i \u0111i\u1ec7n n\u0103ng l\u00ean g\u1ea5p \u0111\u00f4i th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed tr\u00ean \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n s\u1ebd ","select":["A. gi\u1ea3m \u0111i t\u00e1m l\u1ea7n.","B. gi\u1ea3m \u0111i b\u1ed1n l\u1ea7n. ","C. gi\u1ea3m \u0111i hai l\u1ea7n.","D. kh\u00f4ng thay \u0111\u1ed5i."],"hint":"","explain":"<span class='basic_left'>$P=U\\times I={{I}^{2}}\\times R={{\\frac{U}{R}}^{2}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3340},{"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":"Tr\u00ean m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n x\u00e1c \u0111\u1ecbnh d\u01b0\u1edbi hi\u1ec7u \u0111i\u1ec7n th\u1ebf 100 000V. Ph\u1ea3i d\u00f9ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u1edf hai \u0111\u1ea7u d\u00e2y n\u00e0y l\u00e0 bao nhi\u00eau \u0111\u1ec3 c\u00f4ng su\u1ea5t hao ph\u00ed gi\u1ea3m \u0111i hai l\u1ea7n? ","select":["A. 200 000V ","B. 400 000V","C. 141 000V","D. 50 000V"],"hint":"","explain":"<span class='basic_left'>C\u00f4ng su\u1ea5t hao ph\u00ed d\u01b0\u1edbi hi\u1ec7u \u0111i\u1ec7n th\u1ebf U = 100000V<br\/>${{P}_{hp}}=\\dfrac{R{{P}^{2}}}{{{100000}^{2}}}$ (1) <br\/>\u0110\u1ec3 gi\u1ea3m hao ph\u00ed hai l\u1ea7n th\u00ec: <br\/>$\\dfrac{{{P}_{hp}}}{2}=\\dfrac{R{{P}^{2}}}{{{U}^{2}}}$ (2) <br\/>L\u1ea5y (2) chia cho (1) ta \u0111\u01b0\u1ee3c: $\\dfrac{\\dfrac{{{P}_{hp}}}{2}}{{{P}_{hp}}}=\\dfrac{\\dfrac{R{{P}^{2}}}{{{U}^{2}}}}{\\dfrac{R{{P}^{2}}}{{{100000}^{2}}}}$ <br\/>T\u01b0\u01a1ng \u0111\u01b0\u01a1ng: $\\dfrac{{{100000}^{2}}}{{{U}^{2}}}=\\dfrac{1}{2}$ (chia ph\u00e2n s\u1ed1 b\u1eb1ng nh\u00e2n ngh\u1ecbch \u0111\u1ea3o) <br\/>T\u01b0\u01a1ng \u0111\u01b0\u01a1ng: ${{U}^{2}}={{2.100000}^{2}}$ <br\/>Suy ra: U=141000V<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3341},{"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":"C\u00f3 hai \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n t\u1ea3i \u0111i c\u00f9ng m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n v\u1edbi d\u00e2y d\u1eabn c\u00f9ng ti\u1ebft di\u1ec7n, l\u00e0m c\u00f9ng b\u1eb1ng m\u1ed9t ch\u1ea5t. \u0110\u01b0\u1eddng d\u00e2y th\u1ee9 nh\u1ea5t c\u00f3 chi\u1ec1u d\u00e0i 100 Km v\u00e0 hi\u1ec7u \u0111i\u1ec7n th\u1ebf \u1edf hai \u0111\u1ea7u d\u00e2y l\u00e0 100 000kV. \u0110\u01b0\u1eddng d\u00e2y th\u1ee9 hai c\u00f3 chi\u1ec1u d\u00e0i 200Km v\u00e0 hi\u1ec7u \u0111i\u1ec7n th\u1ebf 200000kV. So s\u00e1nh c\u00f4ng su\u1ea5t hao ph\u00ed v\u00ec to\u1ea3 nhi\u1ec7t ${{P}_{1}}$v\u00e0 ${{P}_{2}}$ c\u1ee7a hai \u0111\u01b0\u1eddng d\u00e2y? ","select":["A. ${{P}_{1}}$ = ${{P}_{2}}$ ","B. ${{P}_{1}}$= 2 ${{P}_{2}}$ ","C. ${{P}_{1}}$= 4 ${{P}_{2}}$ ","D. ${{P}_{1}}$= 1\/2 ${{P}_{2}}$ "],"hint":"","explain":"<span class='basic_left'>C\u00f4ng su\u1ea5t hao ph\u00ed trong tr\u01b0\u1eddng h\u1ee3p 1<br\/>${{P}_{hp1}}=\\dfrac{R{{P}^{2}}}{{{({{U}_{1}})}^{2}}}=\\dfrac{\\rho {{l}_{1}}{{P}^{2}}}{S.{{({{U}_{1}})}^{2}}}=\\dfrac{100\\rho {{P}^{2}}}{S{{.100000}^{2}}}$(1) <br\/>C\u00f4ng su\u1ea5t hao ph\u00ed trong tr\u01b0\u1eddng h\u1ee3p 2<br\/>${{P}_{hp2}}=\\dfrac{R{{P}^{2}}}{{{({{U}_{2}})}^{2}}}=\\dfrac{\\rho {{l}_{2}}{{P}^{2}}}{S.{{({{U}_{2}})}^{2}}}=\\dfrac{200\\rho {{P}^{2}}}{S{{.200000}^{2}}}$ (2) <br\/>Do hai d\u00e2y d\u1eabn c\u00f9ng l\u00e0m b\u1eb1ng m\u1ed9t ch\u1ea5t li\u1ec7u, c\u00f9ng m\u1ed9t c\u00f4ng su\u1ea5t truy\u1ec1n t\u1ea3i v\u00e0 c\u00f9ng m\u1ed9t ti\u1ebft di\u1ec7n n\u00ean \u03c1, P, S c\u1ee7a hai d\u00e2y b\u1eb1ng nhau. <br\/>L\u1ea5y (2) chia cho (1) ta \u0111\u01b0\u1ee3c: ${{P}_{1}}$ = 2 ${{P}_{2}}$<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3342},{"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 truy\u1ec1n t\u1ea3i m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n 1000kW b\u1eb1ng m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y c\u00f3 \u0111i\u1ec7n tr\u1edf 10\u2126. Hi\u1ec7u \u0111i\u1ec7n th\u1ebf gi\u1eefa hai \u0111\u1ea7u d\u00e2y t\u1ea3i \u0111i\u1ec7n l\u00e0 110kV. C\u00f4ng su\u1ea5t hao ph\u00ed tr\u00ean \u0111\u01b0\u1eddng d\u00e2y l\u00e0 ","select":["A. 9,1W.","B. 1100W.","C. 82,64W.","D. 826,4W."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":3343},{"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 truy\u1ec1n \u0111i c\u00f9ng m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n, n\u1ebfu \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n d\u00e0i g\u1ea5p \u0111\u00f4i th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed v\u00ec t\u1ecfa nhi\u1ec7t s\u1ebd? ","select":["A. T\u0103ng 2 l\u1ea7n. ","B. T\u0103ng 4 l\u1ea7n","C. Gi\u1ea3m 2 l\u1ea7n.","D. Kh\u00f4ng t\u0103ng, kh\u00f4ng gi\u1ea3m."],"hint":"","explain":"<span class='basic_left'> \u0110\u1ec3 truy\u1ec1n \u0111i c\u00f9ng m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n, n\u1ebfu \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n d\u00e0i g\u1ea5p \u0111\u00f4i th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed v\u00ec t\u1ecfa nhi\u1ec7t s\u1ebd t\u0103ng 2 l\u1ea7n.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3344},{"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":" Tr\u00ean c\u00f9ng m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y d\u1eabn t\u1ea3i \u0111i c\u00f9ng m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n, n\u1ebfu d\u00f9ng d\u00e2y d\u1eabn c\u00f3 ti\u1ebft di\u1ec7n t\u0103ng g\u1ea5p \u0111\u00f4i th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed v\u00ec t\u1ecfa nhi\u1ec7t s\u1ebd?","select":["A. T\u0103ng 2 l\u1ea7n.","B. Gi\u1ea3m 2 l\u1ea7n.","C. T\u0103ng 4 l\u1ea7n.","D. Gi\u1ea3m 4 l\u1ea7n."],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3 c\u00f4ng th\u1ee9c t\u00ednh c\u00f4ng su\u1ea5t hao ph\u00ed l\u00e0 ${{P}_{hp}}=\\dfrac{R.{{P}^{2}}}{{{U}^{2}}}$ . <br\/>Theo c\u00f4ng th\u1ee9c th\u00ec ${{P}_{hp}}$ t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111i\u1ec7n tr\u1edf R m\u00e0 R th\u00ec t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi ti\u1ebft di\u1ec7n S c\u1ee7a d\u00e2y theo c\u00f4ng th\u1ee9c R=(\u03c1.l)\/S. <br\/> Do v\u1eady khi ti\u1ebft di\u1ec7n d\u00e2y d\u1eabn S t\u0103ng 2 l\u1ea7n th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed gi\u1ea3m 2 l\u1ea7n.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3345},{"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 truy\u1ec1n t\u1ea3i \u0111i\u1ec7n n\u0103ng \u0111i xa, \u0111i\u1ec7n n\u0103ng hao ph\u00ed tr\u00ean \u0111\u01b0\u1eddng d\u00e2y d\u1eabn ch\u1ee7 y\u1ebfu l\u00e0 do","select":["A. t\u00e1c d\u1ee5ng t\u1eeb c\u1ee7a d\u00f2ng \u0111i\u1ec7n.","B. t\u00e1c d\u1ee5ng nhi\u1ec7t c\u1ee7a d\u00f2ng \u0111i\u1ec7n.","C. t\u00e1c d\u1ee5ng h\u00f3a h\u1ecdc c\u1ee7a d\u00f2ng \u0111i\u1ec7n.","D. t\u00e1c d\u1ee5ng sinh l\u00fd c\u1ee7a d\u00f2ng \u0111i\u1ec7n."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3346},{"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":" Nh\u1eefng ph\u01b0\u01a1ng \u00e1n c\u00f3 th\u1ec3 l\u00e0m gi\u1ea3m hao ph\u00ed tr\u00ean \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i\u1ec7n l\u00e0 ","select":["A. gi\u1ea3m \u0111i\u1ec7n tr\u1edf d\u00e2y d\u1eabn, t\u0103ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf truy\u1ec1n t\u1ea3i.","B. gi\u1ea3m \u0111i\u1ec7n tr\u1edf d\u00e2y d\u1eabn, gi\u1ea3m hi\u1ec7u \u0111i\u1ec7n th\u1ebf truy\u1ec1n t\u1ea3i.","C. t\u0103ng \u0111i\u1ec7n tr\u1edf d\u00e2y d\u1eabn, gi\u1ea3m hi\u1ec7u \u0111i\u1ec7n th\u1ebf truy\u1ec1n t\u1ea3i.","D. t\u0103ng \u0111i\u1ec7n tr\u1edf d\u00e2y d\u1eabn, t\u0103ng hi\u1ec7u \u0111i\u1ec7n th\u1ebf truy\u1ec1n t\u1ea3i."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":3347},{"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 truy\u1ec1n t\u1ea3i \u0111i\u1ec7n n\u0103ng \u0111i xa, \u0111i\u1ec7n n\u0103ng hao ph\u00ed \u0111\u00e3 chuy\u1ec3n ho\u00e1 th\u00e0nh d\u1ea1ng n\u0103ng l\u01b0\u1ee3ng ","select":["A. ho\u00e1 n\u0103ng.","B. n\u0103ng l\u01b0\u1ee3ng \u00e1nh s\u00e1ng.","C. nhi\u1ec7t n\u0103ng.","D. n\u0103ng l\u01b0\u1ee3ng t\u1eeb tr\u01b0\u1eddng. "],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3348},{"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":"Tr\u00ean c\u00f9ng m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y t\u1ea3i \u0111i m\u1ed9t c\u00f4ng su\u1ea5t \u0111i\u1ec7n x\u00e1c \u0111\u1ecbnh d\u01b0\u1edbi m\u1ed9t hi\u1ec7u \u0111i\u1ec7n th\u1ebf x\u00e1c \u0111\u1ecbnh, n\u1ebfu d\u00f9ng d\u00e2y d\u1eabn c\u00f3 \u0111\u01b0\u1eddng k\u00ednh ti\u1ebft di\u1ec7n gi\u1ea3m \u0111i m\u1ed9t n\u1eeda th\u00ec c\u00f4ng su\u1ea5t hao ph\u00ed v\u00ec to\u1ea3 nhi\u1ec7t s\u1ebd thay \u0111\u1ed5i nh\u01b0 th\u1ebf n\u00e0o? ","select":["A. T\u0103ng l\u00ean hai l\u1ea7n.","B. T\u0103ng l\u00ean b\u1ed1n l\u1ea7n.","C. Gi\u1ea3m \u0111i hai l\u1ea7n.","D. Gi\u1ea3m \u0111i b\u1ed1n l\u1ea7n."],"hint":"","explain":"<span class='basic_left'>Ta c\u00f3 c\u00f4ng th\u1ee9c t\u00ednh ti\u1ebft di\u1ec7n d\u00e2y d\u1eabn tr\u00f2n l\u00e0: $S=\\dfrac{\\pi .{{d}^{2}}}{4}$ (d: l\u00e0 \u0111\u01b0\u1eddng k\u00ednh c\u1ee7a ti\u1ebft di\u1ec7n d\u00e2y d\u1eabn). Do \u0111\u01b0\u1eddng k\u00ednh gi\u1ea3m \u0111i m\u1ed9t n\u1eefa n\u00ean ti\u1ebft di\u1ec7n gi\u1ea3m \u0111i 4 l\u1ea7n (S t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi d2 ). S gi\u1ea3m \u0111i 4 l\u1ea7n n\u00ean \u0111i\u1ec7n tr\u1edf R t\u0103ng 4 l\u1ea7n (S t\u1ec9 l\u1ec7 ngh\u1ecbch v\u1edbi \u0111i\u1ec7n tr\u1edf). R t\u0103ng 4 l\u1ea7n n\u00ean c\u00f4ng su\u1ea5t hao ph\u00ed Php t\u0103ng 4 l\u1ea7n (do Php t\u1ec9 l\u1ec7 thu\u1eadn v\u1edbi \u0111i\u1ec7n tr\u1edf R).<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3349},{"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":" Khi truy\u1ec1n t\u1ea3i \u0111i\u1ec7n n\u0103ng, \u1edf n\u01a1i truy\u1ec1n \u0111i ng\u01b0\u1eddi ta c\u1ea7n l\u1eafp ","select":["A. bi\u1ebfn th\u1ebf t\u0103ng \u0111i\u1ec7n \u00e1p.","B. bi\u1ebfn th\u1ebf gi\u1ea3m \u0111i\u1ec7n \u00e1p.","C. bi\u1ebfn th\u1ebf \u1ed5n \u00e1p.","D. c\u1ea3 bi\u1ebfn th\u1ebf t\u0103ng \u00e1p v\u00e0 bi\u1ebfn th\u1ebf h\u1ea1 \u00e1p."],"hint":"","explain":"<span class='basic_left'><br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3350}],"lesson":{"save":0,"level":2}}