{"common":{"save":0,"post_id":"8232","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"9470","post_id":"8232","mon_id":"1159533","chapter_id":"1159595","question":"<p>M\u1ed9t kính lúp có tiêu c\u1ef1 f = 10 cm. M\u1ed9t v\u1eadt \u0111\u01b0\u1ee3c \u0111\u1eb7t cách kính lúp 8 cm. \u0110\u1ed9 phóng \u0111\u1ea1i \u1ea3nh là:<\/p>","options":["A. 1,5","B. 2,5","C. 5","D. 3,3"],"correct":"4","level":"3","hint":"","answer":"<p>\u0110áp án: D. 3,3<\/p><p>Gi\u1ea3i thích:<\/p><p>Công th\u1ee9c \u0111\u1ed9 phóng \u0111\u1ea1i: <span class=\"math-tex\">$M = {d_{ng\u01b0\u1eddi} \\over d_{v\u1eadt}} = {25 \\over 8} \u2248 3,3$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-12-31 11:43:18","option_type":"txt","len":0},{"id":"9471","post_id":"8232","mon_id":"1159533","chapter_id":"1159595","question":"<p>M\u1ed9t th\u1ea5u kính h\u1ed9i t\u1ee5 có tiêu c\u1ef1 f = 20 cm. M\u1ed9t v\u1eadt \u0111\u01b0\u1ee3c \u0111\u1eb7t cách th\u1ea5u kính 30 cm. \u1ea2nh qua th\u1ea5u kính cách th\u1ea5u kính bao xa?<\/p>","options":["A. 20 cm","B. 30 cm","C. 60 cm","D. 40 cm"],"correct":"3","level":"3","hint":"","answer":"<p>\u0110áp án: C. 60 cm<\/p><p>Gi\u1ea3i thích:<\/p><p>Dùng công th\u1ee9c: <span class=\"math-tex\">${1 \\over f} = {1 \\over d} + {1 \\over d’} => {1 \\over d’} = {1 \\over f} - {1 \\over d} = {1 \\over 20} - {1 \\over 30} = { 1 \\over 60}$<\/span><\/p><p>=> d' = 60 cm<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-12-31 11:55:57","option_type":"txt","len":0},{"id":"9472","post_id":"8232","mon_id":"1159533","chapter_id":"1159595","question":"<p>M\u1ed9t kính lúp có tiêu c\u1ef1 f = 15 cm. V\u1eadt nh\u1ecf \u0111\u01b0\u1ee3c \u0111\u1eb7t cách kính lúp 9 cm. \u1ea2nh t\u1ea1o ra qua kính lúp là:<\/p>","options":["A. \u1ea2nh th\u1eadt, l\u1edbn h\u01a1n v\u1eadt.","B. \u1ea2nh \u1ea3o, cùng chi\u1ec1u, l\u1edbn h\u01a1n v\u1eadt.","C. \u1ea2nh \u1ea3o, ng\u01b0\u1ee3c chi\u1ec1u, nh\u1ecf h\u01a1n v\u1eadt.","D. \u1ea2nh th\u1eadt, cùng chi\u1ec1u, nh\u1ecf h\u01a1n v\u1eadt."],"correct":"2","level":"3","hint":"","answer":"<p>\u0110áp án: B. \u1ea2nh \u1ea3o, cùng chi\u1ec1u, l\u1edbn h\u01a1n v\u1eadt.<\/p><p>Gi\u1ea3i thích:<\/p><p>Vì v\u1eadt \u0111\u1eb7t trong kho\u1ea3ng tiêu c\u1ef1 (d < f), th\u1ea5u kính h\u1ed9i t\u1ee5 t\u1ea1o \u1ea3nh \u1ea3o, cùng chi\u1ec1u và l\u1edbn h\u01a1n v\u1eadt.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-12-31 12:13:35","option_type":"txt","len":2}]}
