{"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":"Trong loa \u0111i\u1ec7n, l\u1ef1c n\u00e0o l\u00e0m cho m\u00e0ng loa dao \u0111\u1ed9ng ph\u00e1t ra \u00e2m?","select":["A. L\u1ef1c h\u00fat c\u1ee7a nam ch\u00e2m \u0111i\u1ec7n t\u00e1c d\u1ee5ng v\u00e0o m\u00e0ng loa l\u00e0m b\u1eb1ng s\u1eaft non.","B. L\u1ef1c t\u1eeb c\u1ee7a m\u1ed9t nam ch\u00e2m v\u0129nh c\u1eedu t\u00e1c d\u1ee5ng l\u00ean cu\u1ed9n d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n bi\u1ebfn \u0111\u1ed5i ch\u1ea1y qua g\u1eafn v\u00e0o m\u00e0ng loa.","C. L\u1ef1c t\u1eeb c\u1ee7a m\u1ed9t nam ch\u00e2m v\u0129nh c\u1eedu t\u00e1c d\u1ee5ng v\u00e0o mi\u1ebfng s\u1eaft g\u1eafn v\u00e0o m\u00e0ng loa.","D. L\u1ef1c t\u1eeb c\u1ee7a m\u1ed9t nam ch\u00e2m \u0111i\u1ec7n t\u00e1c d\u1ee5ng v\u00e0o m\u1ed9t cu\u1ed9n d\u00e2y d\u1eabn k\u00edn g\u1eafn v\u00e0o m\u00e0ng loa."],"hint":"","explain":"<span class='basic_left'>Trong loa \u0111i\u1ec7n, l\u1ef1c l\u00e0m cho m\u00e0ng loa dao \u0111\u1ed9ng ph\u00e1t ra \u00e2m l\u00e0: <br\/>L\u1ef1c t\u1eeb c\u1ee7a m\u1ed9t nam ch\u00e2m v\u0129nh c\u1eedu t\u00e1c d\u1ee5ng l\u00ean cu\u1ed9n d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n bi\u1ebfn \u0111\u1ed5i ch\u1ea1y qua g\u1eafn v\u00e0o m\u00e0ng loa.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":1}]}],"id_ques":3151},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/vatly/bai26/lv2/img\/h2.jpg'\/><\/center>Trong chu\u00f4ng b\u00e1o \u0111\u1ed9ng g\u1eafn v\u00e0o c\u1eeda \u0111\u1ec3 khi c\u1eeda b\u1ecb m\u1edf th\u00ec chu\u00f4ng k\u00eau, r\u01a1le \u0111i\u1ec7n t\u1eeb c\u00f3 t\u00e1c d\u1ee5ng t\u1eeb? ","select":["A. L\u00e0m b\u1eadt m\u1ed9t l\u00f2 xo \u0111\u00e0n h\u1ed3i g\u00f5 v\u00e0o chu\u00f4ng.","B. \u0110\u00f3ng c\u00f4ng t\u1eafc c\u1ee7a chu\u00f4ng \u0111i\u1ec7n l\u00e0m cho chu\u00f4ng k\u00eau.","C. L\u00e0m cho c\u00e1nh c\u1eeda m\u1edf \u0111\u1eadp m\u1ea1nh v\u00e0o chu\u00f4ng.","D. L\u00e0m cho c\u00e1nh c\u1eeda r\u00fat ch\u1ed1t h\u00e3m c\u1ea7n rung chu\u00f4ng."],"hint":"","explain":"<span class='basic_left'>Trong chu\u00f4ng b\u00e1o \u0111\u1ed9ng g\u1eafn v\u00e0o c\u1eeda \u0111\u1ec3 khi c\u1eeda b\u1ecb m\u1edf th\u00ec chu\u00f4ng k\u00eau, r\u01a1le \u0111i\u1ec7n t\u1eeb c\u00f3 t\u00e1c d\u1ee5ng t\u1eeb:<br\/>V\u00ec khi c\u01b0\u0309a bi\u0323 he\u0301 m\u01a1\u0309, chu\u00f4ng k\u00eau vi\u0300 c\u01b0\u0309a m\u01a1\u0309 \u0111a\u0303 la\u0300m h\u01a1\u0309 ma\u0323ch \u0111i\u00ea\u0323n 1 , nam ch\u00e2m \u0111i\u00ea\u0323n m\u00e2\u0301t h\u00ea\u0301t t\u01b0\u0300 ti\u0301nh , mi\u00ea\u0301ng s\u0103\u0301t r\u01a1i xu\u00f4\u0301ng va\u0300 t\u01b0\u0323 \u0111\u00f4\u0323ng \u0111o\u0301ng ma\u0323ch \u0111i\u00ea\u0323n 2.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":1}]}],"id_ques":3152},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/vatly/bai26/lv2/img\/h3.jpg'\/><\/center>X\u00e9t c\u00e1c b\u1ed9 ph\u1eadn ch\u00ednh c\u1ee7a m\u1ed9t loa \u0111i\u1ec7n<br\/>(1). nam ch\u00e2m.<br\/>(2). \u1ed1ng d\u00e2y.<br\/>(3). m\u00e0ng loa.<br\/>C\u00e1c b\u1ed9 ph\u1eadn tr\u1ef1c ti\u1ebfp g\u00e2y ra \u00e2m l\u00e0:","select":["A. (2)","B. (3)","C. (2) + (3)","D. (1)"],"hint":"","explain":"<span class='basic_left'>Loa c\u0169ng ph\u1ea3i c\u00f3 m\u1ed9t b\u1ed9 ph\u1eadn quan tr\u1ecdng g\u1ecdi l\u00e0 m\u00e0ng rung (ho\u1eb7c m\u00e0ng loa). M\u00e0ng rung l\u00e0 n\u01a1i \u00e2m thanh \u0111\u01b0\u1ee3c ph\u00e1t ra \u0111\u1ec3 \u0111\u1ebfn v\u1edbi tai ng\u01b0\u1eddi nghe. Tu\u1ef3 t\u1eebng lo\u1ea1i loa kh\u00e1c nhau m\u00e0 nguy\u00ean l\u00fd l\u00e0m rung m\u00e0ng rung l\u00e0 kh\u00e1c nhau.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3153},{"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 c\u00e1c v\u1eadt d\u1ee5ng sau \u0111\u00e2y : b\u00e0n l\u00e0 \u0111i\u1ec7n, la b\u00e0n, chu\u00f4ng \u0111i\u1ec7n, r\u01a1le \u0111i\u1ec7n t\u1eeb. V\u1eadt n\u00e0o c\u00f3 s\u1eed d\u1ee5ng nam ch\u00e2m v\u0129nh c\u1eedu ?","select":["A. Chu\u00f4ng \u0111i\u1ec7n","B. R\u01a1le \u0111i\u1ec7n t\u1eeb ","C. La b\u00e0n","D. B\u00e0n l\u00e0 \u0111i\u1ec7n"],"hint":"","explain":"<span class='basic_left'>V\u1eadt c\u00f3 s\u1eed d\u1ee5ng nam ch\u00e2m v\u0129nh c\u1eedu: la b\u00e0n<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3154},{"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":"Trong b\u1ec7nh vi\u1ec7n, l\u00e0m th\u1ebf n\u00e0o m\u00e0 c\u00e1c b\u00e1c s\u0129 ph\u1eabu thu\u1eadt c\u00f3 th\u1ec3 l\u1ea5y c\u00e1c m\u1ea1t s\u1eaft nh\u1ecf li ti ra kh\u1ecfi m\u1eaft c\u1ee7a b\u1ec7nh nh\u00e2n ? H\u00e3y t\u00ecm hi\u1ec3u v\u00e0 ch\u1ecdn c\u00e1ch l\u00e0m \u0111\u00fang trong c\u00e1c c\u00e1ch l\u00e0m sau:","select":["A. D\u00f9ng nam ch\u00e2m ","B. D\u00f9ng m\u1ed9t vi\u00ean pin c\u00f2n t\u1ed1t","C. D\u00f9ng panh.","D. D\u00f9ng k\u00ecm."],"hint":"","explain":"<span class='basic_left'>Trong b\u00ea\u0323nh vi\u00ea\u0323n ba\u0301c si\u0303 co\u0301 th\u00ea\u0309 l\u00e2\u0301y ma\u0323t s\u0103\u0301t nho\u0309 liti ra kho\u0309i m\u0103\u0301t b\u00ea\u0323nh nh\u00e2n b\u0103\u0300ng ca\u0301ch \u0111\u01b0a nam ch\u00e2m la\u0323i g\u00e2\u0300n vi\u0323 tri\u0301 co\u0301 ma\u0323t s\u0103\u0301t, nam ch\u00e2m t\u01b0\u0323 \u0111\u00f4\u0323ng hu\u0301t ma\u0323t s\u0103\u0301t ra kho\u0309i m\u0103\u0301t.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":2}]}],"id_ques":3155},{"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 nam ch\u00e2m \u0111i\u1ec7n g\u1ed3m cu\u1ed9n d\u00e2y","select":["A. kh\u00f4ng c\u00f3 l\u00f5i","B. c\u00f3 l\u00f5i l\u00e0 m\u1ed9t thanh th\u00e9p","C. c\u00f3 l\u00f5i l\u00e0 m\u1ed9t thanh s\u1eaft non","D. c\u00f3 l\u00f5i l\u00e0 m\u1ed9t thanh nam ch\u00e2m."],"hint":"","explain":"<span class='basic_left'>M\u1ed9t nam ch\u00e2m \u0111i\u1ec7n g\u1ed3m cu\u1ed9n d\u00e2y c\u00f3 l\u00f5i l\u00e0 m\u1ed9t thanh s\u1eaft non<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3156},{"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\u1eadt n\u00e0o sau \u0111\u00e2y kh\u00f4ng c\u00f3 \u1ee9ng d\u1ee5ng c\u1ee7a nam ch\u00e2m?","select":["A. Chu\u00f4ng \u0111i\u1ec7n.","B. T\u00e0u \u0111i\u1ec7n.","C. Loa \u0111i\u1ec7n.","D. Chu\u00f4ng gi\u00f3."],"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":3157},{"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\u00e1c d\u1ee5ng c\u1ee7a nam ch\u00e2m \u0111i\u1ec7n trong thi\u1ebft b\u1ecb r\u01a1le d\u00f2ng l\u00e0:","select":["A. ng\u1eaft m\u1ea1ch \u0111i\u1ec7n cho \u0111\u1ed9ng c\u01a1 ng\u1eebng l\u00e0m vi\u1ec7c.","B. \u0111\u00f3ng m\u1ea1ch \u0111i\u1ec7n cho \u0111\u1ed9ng c\u01a1 l\u00e0m vi\u1ec7c.","C. ng\u1eaft m\u1ea1ch \u0111i\u1ec7n cho nam ch\u00e2m \u0111i\u1ec7n.","D. \u0111\u00f3ng m\u1ea1ch \u0111i\u1ec7n cho nam ch\u00e2m \u0111i\u1ec7n."],"hint":"","explain":"<span class='basic_left'>T\u00e1c d\u1ee5ng c\u1ee7a nam ch\u00e2m \u0111i\u1ec7n trong thi\u1ebft b\u1ecb r\u01a1le d\u00f2ng l\u00e0 ng\u1eaft m\u1ea1ch \u0111i\u1ec7n cho \u0111\u1ed9ng c\u01a1 ng\u1eebng l\u00e0m vi\u1ec7c.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":3158},{"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\u1ee5ng c\u1ee5 n\u00e0o d\u01b0\u1edbi \u0111\u00e2y \u0111\u01b0\u1ee3c \u1ee9ng d\u1ee5ng t\u1eeb nh\u1eefng t\u00ednh ch\u1ea5t c\u1ee7a nam ch\u00e2m?","select":["A. Chu\u00f4ng xe \u0111\u1ea1p","B. Chu\u00f4ng ch\u00f9a","C. Chu\u00f4ng g\u1ecdi c\u1eeda","D. Chu\u00f4ng gi\u00f3."],"hint":"","explain":"<span class='basic_left'>Chu\u00f4ng g\u1ecdi c\u1eeda l\u00e0 chu\u00f4ng \u0111i\u1ec7n \u0111\u01b0\u1ee3c \u1ee9ng d\u1ee5ng t\u1eeb nh\u1eefng t\u00ednh ch\u1ea5t c\u1ee7a nam ch\u00e2m.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3159},{"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":"Ph\u00e1t bi\u1ec3u n\u00e0o sau \u0111\u00e2y l\u00e0 \u0111\u00fang nh\u1ea5t khi n\u00f3i v\u1ec1 t\u01b0\u01a1ng t\u00e1c gi\u1eefa hai nam ch\u00e2m?","select":["A. C\u00e1c c\u1ef1c c\u00f9ng t\u00ean h\u00fat nhau, c\u00e1c c\u1ef1c kh\u00e1c t\u00ean th\u00ec \u0111\u1ea9y nhau.","B. C\u00e1c c\u1ef1c kh\u00e1c t\u00ean th\u00ec h\u00fat nhau, c\u00e1c c\u1ef1c c\u00f9ng t\u00ean c\u0169ng h\u00fat nhau.","C. C\u00e1c c\u1ef1c c\u00f9ng t\u00ean th\u00ec \u0111\u1ea9y nhau, c\u00e1c c\u1ef1c kh\u00e1c t\u00ean th\u00ec h\u00fat nhau, song l\u1ef1c h\u00fat hay \u0111\u1ea9y ch\u1ec9 c\u1ea3m th\u1ea5y \u0111\u01b0\u1ee3c khi ch\u00fang \u1edf g\u1ea7n nhau.","D. C\u00e1c c\u1ef1c h\u00fat nhau hay \u0111\u1ea9y nhau t\u00f9y theo \u0111i\u1ec1u ki\u1ec7n c\u1ee5 th\u1ec3."],"hint":"","explain":"<span class='basic_left'> Ph\u00e1t bi\u1ec3u v\u1ec1 t\u01b0\u01a1ng t\u00e1c gi\u1eefa hai nam ch\u00e2m l\u00e0:<br\/>C\u00e1c c\u1ef1c c\u00f9ng t\u00ean th\u00ec \u0111\u1ea9y nhau, c\u00e1c c\u1ef1c kh\u00e1c t\u00ean th\u00ec h\u00fat nhau, song l\u1ef1c h\u00fat hay \u0111\u1ea9y ch\u1ec9 c\u1ea3m th\u1ea5y \u0111\u01b0\u1ee3c khi ch\u00fang \u1edf g\u1ea7n nhau.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":1}]}],"id_ques":3160},{"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":"Trong c\u00e1c thi\u1ebft b\u1ecb sau, thi\u1ebft b\u1ecb n\u00e0o kh\u00f4ng d\u00f9ng nam ch\u00e2m \u0111i\u1ec7n v\u00e0 nam ch\u00e2m v\u0129nh c\u1eedu:","select":["A. \u0110i\u1ec7n tho\u1ea1i","B. C\u00f4ng t\u1eafc \u0111i\u1ec7n th\u00f4ng th\u01b0\u1eddng","C. Chu\u00f4ng \u0111i\u1ec7n","D. V\u00f4 tuy\u1ebfn truy\u1ec1n h\u00ecnh"],"hint":"","explain":"<span class='basic_left'>\u0110i\u1ec7n tho\u1ea1i, chu\u00f4ng \u0111i\u1ec7n v\u00e0 v\u00f4 tuy\u1ebfn truy\u1ec1n h\u00ecnh \u0111\u1ec1u s\u1eed d\u1ee5ng c\u00e1c \u1ee9ng d\u1ee5ng c\u1ee7a nam ch\u00e2m \u0111i\u1ec7n v\u00e0 nam ch\u00e2m v\u0129nh c\u1eedu. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":2}]}],"id_ques":3161},{"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":"Nam ch\u00e2m \u0111i\u1ec7n \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c thi\u1ebft b\u1ecb n\u00e0o sau \u0111\u00e2y?","select":["A. Loa \u0111i\u1ec7n","B. \u0110\u1ed9ng c\u01a1 \u0111i\u1ec7n","C. Chu\u00f4ng b\u00e1o \u0111\u1ed9ng","D. C\u1ea3 3 lo\u1ea1i tr\u00ean"],"hint":"","explain":"<span class='basic_left'>Nam ch\u00e2m \u0111i\u1ec7n \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c thi\u1ebft b\u1ecb loa \u0111i\u1ec7n, chu\u00f4ng b\u00e1o \u0111\u1ed9ng v\u00e0 c\u1ea3 \u0111\u1ed9ng c\u01a1 \u0111i\u1ec7n.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":3162},{"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":"Mu\u1ed1n c\u00f3 m\u1ed9t cu\u1ed9n d\u00e2y \u0111\u1ec3 l\u00e0m nam ch\u00e2m \u0111i\u1ec7n m\u1ea1nh. \u0110i\u1ec1u n\u00e0o sau \u0111\u00e2y l\u00e0 c\u1ea7n thi\u1ebft?","select":["A. Qu\u1ea5n cu\u1ed9n d\u00e2y c\u00f3 nhi\u1ec1u v\u00f2ng ","B. Qu\u1ea5n cu\u1ed9n d\u00e2y m\u1ed9t v\u00f2ng nh\u01b0ng ti\u1ebft di\u1ec7n l\u1edbn","C. D\u00f9ng l\u00f5i \u0111\u1eb7c b\u1eb1ng th\u00e9p","D. D\u00f9ng l\u00f5i b\u1eb1ng nhi\u1ec1u l\u00e1 th\u00e9p m\u1ecfng gh\u00e9p l\u1ea1i"],"hint":"","explain":"<span class='basic_left'>N\u00ean d\u00f9ng d\u00e2y d\u1eabn m\u1ea3nh \u0111\u1ec3 qu\u1ea5n nhi\u1ec1u v\u00f2ng. V\u00ec t\u00e1c d\u1ee5ng t\u1eeb c\u1ee7a nam ch\u00e2m \u0111i\u1ec7n t\u0103ng khi s\u1ed1 v\u00f2ng d\u00e2y c\u1ee7a nam ch\u00e2m \u0111i\u1ec7n t\u0103ng m\u00e0 kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o ti\u1ebft di\u1ec7n c\u1ee7a d\u00e2y d\u1eabn.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":3163},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/vatly/bai26/lv2/img\/h13.jpg'\/><\/center>\u0110i\u1ec7n k\u1ebf l\u00e0 d\u1ee5ng c\u1ee5 \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 ph\u00e1t hi\u1ec7n d\u00f2ng \u0111i\u1ec7n. \u0110i\u1ec7n k\u1ebf t\u1ef1 l\u00e0m l\u1ea5y g\u1ed3m m\u1ed9t c\u00e1i h\u1ed9p trong \u0111\u00f3 g\u1eafn c\u1ed1 \u0111\u1ecbnh m\u1ed9t c\u00e1i la b\u00e0n th\u00f4ng th\u01b0\u1eddng v\u1edbi hai cu\u1ed9n d\u00e2y d\u1eabn m\u1eafc n\u1ed1i ti\u1ebfp, c\u00e1ch \u0111i\u1ec7n qu\u1ea5n quanh h\u1ed9p (h\u00ecnh 26.2). M\u1ee9c \u0111\u1ed9 ph\u00e1t hi\u1ec7n \u0111\u01b0\u1ee3c d\u00f2ng \u0111i\u1ec7n y\u1ebfu c\u1ee7a \u0111i\u1ec7n k\u1ebf n\u00e0y ph\u1ee5 thu\u1ed9c v\u00e0o nh\u1eefng y\u1ebfu t\u1ed1 n\u00e0o?","select":["A. Chi\u1ec1u d\u00e0i c\u1ee7a \u0111o\u1ea1n d\u00e2y l\u00e0m \u1ed1ng d\u00e2y.","B. V\u1eadt li\u1ec7u l\u00e0m d\u00e2y.","C. \u0110\u1ed9 l\u1edbn c\u1ee7a c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua \u1ed1ng d\u00e2y.","D. S\u1ed1 v\u00f2ng d\u00e2y c\u1ee7a \u1ed1ng d\u00e2y v\u00e0 \u0111\u1ed9 l\u1edbn c\u1ee7a c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua \u1ed1ng d\u00e2y."],"hint":"","explain":"<span class='basic_left'>M\u1ee9c \u0111\u1ed9 ph\u00e1t hi\u1ec7n \u0111\u01b0\u1ee3c d\u00f2ng \u0111i\u1ec7n y\u1ebfu c\u1ee7a \u0111i\u1ec7n k\u1ebf n\u00e0y ph\u1ee5 thu\u1ed9c v\u00e0o s\u1ed1 v\u00f2ng d\u00e2y c\u1ee7a \u1ed1ng d\u00e2y v\u00e0 \u0111\u1ed9 l\u1edbn c\u1ee7a c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua \u1ed1ng d\u00e2y.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":1}]}],"id_ques":3164},{"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":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop9/vatly/bai26/lv2/img\/h13.jpg'\/><\/center>\u0110i\u1ec7n k\u1ebf l\u00e0 d\u1ee5ng c\u1ee5 \u0111\u01b0\u1ee3c d\u00f9ng \u0111\u1ec3 ph\u00e1t hi\u1ec7n d\u00f2ng \u0111i\u1ec7n. \u0110i\u1ec7n k\u1ebf t\u1ef1 l\u00e0m l\u1ea5y g\u1ed3m m\u1ed9t c\u00e1i h\u1ed9p trong \u0111\u00f3 g\u1eafn c\u1ed1 \u0111\u1ecbnh m\u1ed9t c\u00e1i la b\u00e0n th\u00f4ng th\u01b0\u1eddng v\u1edbi hai cu\u1ed9n d\u00e2y d\u1eabn m\u1eafc n\u1ed1i ti\u1ebfp, c\u00e1ch \u0111i\u1ec7n qu\u1ea5n quanh h\u1ed9p (h\u00ecnh 26.2). Kim c\u1ee7a la b\u00e0n s\u1ebd n\u1eb1m nh\u01b0 th\u1ebf n\u00e0o \u0111\u1ed1i v\u1edbi c\u00e1c v\u00f2ng d\u00e2y khi c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua ha cu\u1ed9n d\u00e2y \u0111\u00f3? V\u1ecb tr\u00ed ban \u0111\u1ea7u c\u1ee7a kim nam ch\u00e2m khi ch\u01b0a c\u00f3 d\u00f2ng \u0111i\u1ec7n \u0111i qua \u0111\u00e3 \u0111\u01b0\u1ee3c ch\u1ec9 ra tr\u00ean h\u00ecnh v\u1ebd.","select":["A. N\u1eb1m song song v\u1edbi d\u00e2y d\u1eabn tr\u00ean b\u1ec1 m\u1eb7t h\u1ed9p.","B. N\u1eb1m vu\u00f4ng g\u00f3c v\u1edbi d\u00e2y d\u1eabn tr\u00ean b\u1ec1 m\u1eb7t h\u1ed9p.","C. N\u1eb1m t\u1ea1o 1 g\u00f3c ${45}^\\circ C$ v\u1edbi d\u00e2y d\u1eabn tr\u00ean b\u1ec1 m\u1eb7t h\u1ed9p.","D. N\u1eb1m t\u1ea1o 1 g\u00f3c ${60}^\\circ C$ v\u1edbi d\u00e2y d\u1eabn tr\u00ean b\u1ec1 m\u1eb7t h\u1ed9p."],"hint":"","explain":"<span class='basic_left'>Kim c\u1ee7a la b\u00e0n s\u1ebd n\u1eb1m d\u1ecdc theo c\u00e1c \u0111\u01b0\u1eddng s\u1ee9c t\u1eeb b\u00ean trong \u1ed1ng d\u00e2y, c\u00f3 ngh\u0129a l\u00e0 n\u1eb1m vu\u00f4ng g\u00f3c v\u1edbi d\u00e2y d\u1eabn tr\u00ean b\u1ec1 m\u1eb7t h\u1ed9p.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/span><\/span> ","column":1}]}],"id_ques":3165},{"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\/>B\u1ed9 ph\u1eadn ch\u00ednh c\u1ee7a loa \u0111i\u1ec7n g\u1ed3m m\u1ed9t \u1ed1ng d\u00e2y L \u0111\u01b0\u1ee3c \u0111\u1eb7t trong t\u1eeb tr\u01b0\u1eddng c\u1ee7a m\u1ed9t \u2026\u2026\u2026, m\u1ed9t \u0111\u1ea7u c\u1ee7a \u1ed1ng d\u00e2y \u0111\u01b0\u1ee3c g\u1eafn ch\u1eb7t v\u1edbi m\u00e0ng loa M.","select":["A. nam ch\u00e2m m\u1ea1nh.","B. thanh s\u1eaft non.","C. d\u00e2y d\u1eabn th\u1eb3ng c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua.","D. m\u1ed9t d\u00e2y d\u1eabn c\u00f3 h\u00ecnh d\u1ea1ng b\u1ea5t k\u00ec c\u00f3 d\u00f2ng \u0111i\u1ec7n ch\u1ea1y qua."],"hint":"","explain":"<span class='basic_left'>B\u1ed9 ph\u1eadn ch\u00ednh c\u1ee7a loa \u0111i\u1ec7n g\u1ed3m m\u1ed9t \u1ed1ng d\u00e2y L \u0111\u01b0\u1ee3c \u0111\u1eb7t trong t\u1eeb tr\u01b0\u1eddng c\u1ee7a m\u1ed9t nam ch\u00e2m m\u1ea1nh, m\u1ed9t \u0111\u1ea7u c\u1ee7a \u1ed1ng d\u00e2y \u0111\u01b0\u1ee3c g\u1eafn ch\u1eb7t v\u1edbi m\u00e0ng loa M.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":3166},{"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 c\u00e1c v\u1eadt d\u1ee5ng sau \u0111\u00e2y : b\u00e0n l\u00e0 \u0111i\u1ec7n, la b\u00e0n, chu\u00f4ng \u0111i\u1ec7n, r\u01a1le \u0111i\u1ec7n t\u1eeb. V\u1eadt n\u00e0o kh\u00f4ng s\u1eed d\u1ee5ng nam ch\u00e2m \u0111i\u1ec7n?","select":["A. Chu\u00f4ng \u0111i\u1ec7n","B. R\u01a1le \u0111i\u1ec7n t\u1eeb","C. La b\u00e0n","D. B\u00e0n l\u00e0 \u0111i\u1ec7n"],"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":3167},{"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":"B\u1ed9 ph\u1eadn n\u00e0o c\u1ee7a loa \u0111i\u1ec7n t\u1ea1o ra dao \u0111\u1ed9ng \u0111\u1ec3 sau \u0111\u00f3 truy\u1ec1n \u0111\u1ebfn m\u00e0ng loa g\u00e2y ra \u00e2m thanh:","select":["A. \u1ed0ng d\u00e2y.","B. M\u00e0ng loa.","C. Nam ch\u00e2m.","D. Nam ch\u00e2m c\u00f9ng v\u1edbi \u1ed1ng d\u00e2y."],"hint":"","explain":"<span class='basic_left'>Nam ch\u00e2m c\u00f9ng v\u1edbi \u1ed1ng d\u00e2y nh\u1eadn t\u00edn hi\u1ec7u \u0111i\u1ec7n sau \u0111\u00f3 t\u1ea1o ra dao \u0111\u1ed9ng \u0111\u1ec3 sau \u0111\u00f3 truy\u1ec1n \u0111\u1ebfn m\u00e0ng loa g\u00e2y ra \u00e2m thanh:<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 D.<\/span><\/span> ","column":2}]}],"id_ques":3168},{"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 cho d\u00f2ng \u0111i\u1ec7n kh\u00f4ng \u0111\u1ed5i v\u00e0o cu\u1ed9n d\u00e2y c\u1ee7a loa \u0111i\u1ec7n th\u00ec loa l\u1ea1i kh\u00f4ng k\u00eau?","select":["A. v\u00ec kh\u00f4ng t\u1ea1o ra \u0111\u01b0\u1ee3c su\u1ea5t \u0111i\u1ec7n \u0111\u1ed9ng c\u1ea3m \u1ee9ng trong cu\u1ed9n d\u00e2y.","B. v\u00ec m\u00e0ng loa rung nh\u1eb9.","C. v\u00ec nam ch\u00e2m kh\u00f4ng c\u00f3 t\u00e1c d\u1ee5ng.","D. v\u00ec cu\u1ed9n d\u00e2y rung nh\u01b0ng m\u00e0ng loa kh\u00f4ng rung."],"hint":"","explain":"<span class='basic_left'>D\u00f2ng \u0111i\u1ec7n kh\u00f4ng \u0111\u1ed5i kh\u00f4ng t\u1ea1o ra \u0111\u01b0\u1ee3c su\u1ea5t \u0111i\u1ec7n \u0111\u1ed9ng c\u1ea3m \u1ee9ng trong cu\u1ed9n d\u00e2y n\u00ean kh\u00f4ng sinh ra l\u1ef1c t\u1eeb t\u01b0\u01a1ng t\u00e1c gi\u1eefa nam ch\u00e2m v\u0129nh c\u1eedu v\u1edbi cu\u1ed9n d\u00e2y n\u00ean m\u00e0ng loa kh\u00f4ng rung.<br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 A.<\/span><\/span> ","column":1}]}],"id_ques":3169},{"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":"Cu\u1ed9n d\u00e2y trong loa \u0111i\u1ec7n ph\u1ea3i c\u00f3 \u0111\u1eb7c \u0111i\u1ec3m g\u00ec th\u00ec loa \u0111i\u1ec7n m\u1edbi c\u00f3 th\u1ec3 k\u00eau?","select":["A. c\u00f3 d\u00f2ng \u0111i\u1ec7n kh\u00f4ng \u0111\u1ed5i \u0111i qua.","B. \u0111\u01b0\u1ee3c cu\u1ed1n \u00edt v\u00f2ng.","C. c\u00f3 d\u00f2ng \u0111i\u1ec7n bi\u1ebfn \u0111\u1ed5i \u0111i qua.","D. l\u00e0m b\u1eb1ng \u0111\u1ed3ng ho\u1eb7c nh\u00f4m."],"hint":"","explain":"<span class='basic_left'>Trong loa \u0111i\u1ec7n, l\u1ef1c n\u00e0o l\u00e0m cho m\u00e0ng loa dao \u0111\u1ed9ng ph\u00e1t ra \u00e2m l\u00e0 l\u1ef1c t\u1eeb c\u1ee7a m\u1ed9t nam ch\u00e2m v\u0129nh c\u1eedu t\u00e1c d\u1ee5ng l\u00ean cu\u1ed9n d\u00e2y c\u00f3 d\u00f2ng \u0111i\u1ec7n bi\u1ebfn \u0111\u1ed5i ch\u1ea1y qua g\u1eafn v\u00e0o m\u00e0ng loa. <br\/> <span class='basic_pink'>V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 C.<\/span><\/span> ","column":2}]}],"id_ques":3170}],"lesson":{"save":0,"level":2}}