Đoạn mạch nối tiếp, song song

Home Lớp 9 Khoa học tự nhiên 9 - sách kết nối tri thức Bài 12: Đoạn mạch nối tiếp, song songBài tập nâng cao

{"common":{"save":0,"post_id":"8248","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"9540","post_id":"8248","mon_id":"1159533","chapter_id":"1159663","question":"M\u1ed9t \u0111o\u1ea1n m\u1ea1ch g\u1ed3m 2 \u0111i\u1ec7n tr\u1edf $R_1 = 4\\ \u03a9$<\/span> và $R_2 = 6\\ \u03a9$<\/span> m\u1eafc n\u1ed1i ti\u1ebfp. Hi\u1ec7u \u0111i\u1ec7n th\u1ebf toàn m\u1ea1ch là 20 V. Nhi\u1ec7t l\u01b0\u1ee3ng t\u1ecfa ra trên $R_1$<\/span> sau 5 giây là:<\/p>","options":["A. 80 J","B. 20 J","C. 40 J","D. 50 J"],"correct":"1","level":"3","hint":"","answer":"\u0110áp án: A. 80 J<\/p>Gi\u1ea3i thích:<\/p>- T\u1ed5ng \u0111i\u1ec7n tr\u1edf: $R = R_1 + R_2 = 4+6=10\\ \u03a9$<\/span><\/p>- Dòng \u0111i\u1ec7n trong m\u1ea1ch: $I = {U \\over R} = {20 \\over 10} = 2\\ A$<\/span><\/p>- Nhi\u1ec7t l\u01b0\u1ee3ng t\u1ecfa ra trên $R_1$<\/span> : $Q = I^2Rt=2^2.4.5=80\\ J$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2025-01-01 10:21:22","option_type":"txt","len":0},{"id":"9541","post_id":"8248","mon_id":"1159533","chapter_id":"1159663","question":"M\u1ed9t \u0111o\u1ea1n m\u1ea1ch song song g\u1ed3m 2 \u0111i\u1ec7n tr\u1edf $R_1 = 8\\ \u03a9$<\/span> và $R_2 = 4\\ \u03a9$<\/span>. Hi\u1ec7u \u0111i\u1ec7n th\u1ebf toàn m\u1ea1ch là 12 V. Tính công su\u1ea5t tiêu th\u1ee5 c\u1ee7a m\u1ea1ch.<\/p>","options":["A. 54 W","B. 36 W","C. 48 W","D. 72 W"],"correct":"1","level":"3","hint":"","answer":"\u0110áp án: A. 54 W<\/p>Gi\u1ea3i thích:<\/p>- \u0110i\u1ec7n tr\u1edf \u0111o\u1ea1n m\u1ea1ch: ${1 \\over R} = {1 \\over R_1} + {1 \\over R_2} = {1 \\over 8} + {1 \\over 4} = 0,375$<\/span><\/p>=> R = 8\/3 Ω<\/p>- Công su\u1ea5t tiêu th\u1ee5 c\u1ee7a m\u1ea1ch: $P= {U^2 \\over R} = {12^2 \\over {8 \\over 3}}= 54\\ W$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2025-01-01 10:31:35","option_type":"txt","len":0},{"id":"9542","post_id":"8248","mon_id":"1159533","chapter_id":"1159663","question":"M\u1ed9t \u0111o\u1ea1n m\u1ea1ch g\u1ed3m 2 \u0111i\u1ec7n tr\u1edf $R_1 = 5\\ \u03a9$<\/span> và $R_2 = 10\\ \u03a9$<\/span> m\u1eafc n\u1ed1i ti\u1ebfp. Hi\u1ec7u \u0111i\u1ec7n th\u1ebf toàn m\u1ea1ch là 15 V. Tính hi\u1ec7u \u0111i\u1ec7n th\u1ebf gi\u1eefa 2 \u0111\u1ea7u $R_2$<\/span>.<\/p>","options":["A. 5 V","B. 10 V","C. 7,5 V","D. 15 V"],"correct":"2","level":"3","hint":"","answer":"\u0110áp án: B. 10 V<\/p>Gi\u1ea3i thích:<\/p>- T\u1ed5ng \u0111i\u1ec7n tr\u1edf: $R= R_1+R_2=5+10=15\\ \u03a9$<\/span><\/p>- Dòng \u0111i\u1ec7n trong m\u1ea1ch: $I ={U \\over R} = {15 \\over 15} =1\\ A$<\/span><\/p>- Hi\u1ec7u \u0111i\u1ec7n th\u1ebf gi\u1eefa 2 \u0111\u1ea7u $R_2$<\/span>: $U_2 = I.R_2=1.10=10\\ V$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2025-01-01 10:39:25","option_type":"txt","len":0}]}