Thực hành xác định khối lượng riêng

Home Lớp 8 Khoa học tự nhiên 8 - sách Kết nối tri thức Bài 14: Thực hành xác định khối lượng riêngBài tập trung bình

{"common":{"save":0,"post_id":"8447","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7215","post_id":"8447","mon_id":"1159539","chapter_id":"1159710","question":"Trong quá trình xác \u0111\u1ecbnh th\u1ec3 tích c\u1ee7a m\u1ed9t v\u1eadt r\u1eafn không th\u1ea5m n\u01b0\u1edbc b\u1eb1ng ph\u01b0\u01a1ng pháp n\u01b0\u1edbc dâng, b\u01b0\u1edbc nào sau \u0111ây là b\u01b0\u1edbc c\u1ea7n thi\u1ebft \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o tính chính xác?<\/p>","options":["A. \u0110\u1ed5 n\u01b0\u1edbc vào bình chia \u0111\u1ed9 cho \u0111\u1ebfn m\u1ee9c cao nh\u1ea5t.","B. Ghi l\u1ea1i m\u1ee9c n\u01b0\u1edbc ban \u0111\u1ea7u tr\u01b0\u1edbc khi cho v\u1eadt vào.","C. L\u1eafc nh\u1eb9 bình \u0111\u1ec3 n\u01b0\u1edbc hòa quy\u1ec7n \u0111\u1ec1u.","D. \u0110o kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a v\u1eadt b\u1eb1ng cân \u0111i\u1ec7n t\u1eed."],"correct":"2","level":"2","hint":"\u0110\u1ec3 tính th\u1ec3 tích c\u1ee7a v\u1eadt theo ph\u01b0\u01a1ng pháp n\u01b0\u1edbc dâng, ta ph\u1ea3i \u0111o m\u1ef1c n\u01b0\u1edbc tr\u01b0\u1edbc và sau khi cho v\u1eadt vào.<\/p>","answer":"\u0110áp án \u0111úng là:<\/strong> B. Ghi l\u1ea1i m\u1ee9c n\u01b0\u1edbc ban \u0111\u1ea7u tr\u01b0\u1edbc khi cho v\u1eadt vào.<\/p>Gi\u1ea3i thích:<\/strong> Vi\u1ec7c ghi l\u1ea1i m\u1ee9c n\u01b0\u1edbc ban \u0111\u1ea7u là b\u01b0\u1edbc quan tr\u1ecdng \u0111\u1ec3 sau khi th\u1ea3 v\u1eadt, ta có th\u1ec3 tính \u0111\u01b0\u1ee3c s\u1ef1 dâng lên c\u1ee7a n\u01b0\u1edbc, t\u1eeb \u0111ó xác \u0111\u1ecbnh chính xác th\u1ec3 tích c\u1ee7a v\u1eadt theo hi\u1ec7u s\u1ed1 c\u1ee7a m\u1ee9c n\u01b0\u1edbc.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2025-02-14 08:09:48","option_type":"txt","len":3},{"id":"7216","post_id":"8447","mon_id":"1159539","chapter_id":"1159710","question":"Khi s\u1eed d\u1ee5ng bình chia \u0111\u1ed9 \u0111\u1ec3 xác \u0111\u1ecbnh th\u1ec3 tích c\u1ee7a m\u1ed9t v\u1eadt, t\u1ea1i sao ta c\u1ea7n \u0111\u1eb7t m\u1eaft ngang v\u1edbi m\u1ef1c n\u01b0\u1edbc?<\/p>","options":["A. \u0110\u1ec3 \u0111o \u0111\u01b0\u1ee3c nhi\u1ec7t \u0111\u1ed9 c\u1ee7a n\u01b0\u1edbc.","B. \u0110\u1ec3 tránh sai s\u1ed1 do góc nhìn gây ra.","C. \u0110\u1ec3 \u0111\u1ea3m b\u1ea3o n\u01b0\u1edbc không b\u1ecb bay h\u01a1i.","D. \u0110\u1ec3 t\u0103ng tính chính xác c\u1ee7a th\u01b0\u1edbc chia \u0111\u1ed9."],"correct":"2","level":"2","hint":"\u0110\u1ecdc k\u1ebft qu\u1ea3 trên bình chia \u0111\u1ed9 c\u1ea7n \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n t\u1eeb v\u1ecb trí ngang v\u1edbi m\u1eb7t n\u01b0\u1edbc (\u0111i\u1ec3m m\u1eaft ph\u1ea3i \u0111\u1ed3ng nh\u1ea5t v\u1edbi \u0111\u01b0\u1eddng m\u1eaft song song v\u1edbi m\u1ef1c n\u01b0\u1edbc) \u0111\u1ec3 tránh sai s\u1ed1 do góc nhìn.<\/p>","answer":"\u0110áp án \u0111úng là:<\/strong> B. \u0110\u1ec3 tránh sai s\u1ed1 do góc nhìn gây ra. Gi\u1ea3i thích:<\/strong> Khi m\u1eaft không \u0111\u1eb7t ngang v\u1edbi m\u1ef1c n\u01b0\u1edbc, ng\u01b0\u1eddi \u0111o s\u1ebd g\u1eb7p hi\u1ec7n t\u01b0\u1ee3ng “l\u1ed7i parallax” (sai s\u1ed1 do góc nhìn), làm cho k\u1ebft qu\u1ea3 \u0111\u1ecdc m\u1ef1c n\u01b0\u1edbc không chính xác.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2025-02-14 08:11:49","option_type":"txt","len":3},{"id":"7217","post_id":"8447","mon_id":"1159539","chapter_id":"1159710","question":"Trong thí nghi\u1ec7m xác \u0111\u1ecbnh kh\u1ed1i l\u01b0\u1ee3ng riêng, t\u1ea1i sao nên s\u1eed d\u1ee5ng v\u1eadt r\u1eafn không th\u1ea5m n\u01b0\u1edbc?<\/p> <\/p>","options":["A. \u0110\u1ec3 \u0111\u1ea3m b\u1ea3o th\u1ec3 tích c\u1ee7a v\u1eadt không b\u1ecb thay \u0111\u1ed5i.","B. \u0110\u1ec3 tránh làm t\u0103ng kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a v\u1eadt khi ti\u1ebfp xúc v\u1edbi n\u01b0\u1edbc.","C. \u0110\u1ec3 t\u0103ng kh\u1ea3 n\u0103ng \u0111o th\u1ec3 tích chính xác.","D. C\u1ea3 A và B \u0111\u1ec1u \u0111úng."],"correct":"4","level":"2","hint":"N\u1ebfu v\u1eadt r\u1eafn th\u1ea5m n\u01b0\u1edbc, kh\u1ed1i l\u01b0\u1ee3ng \u0111o \u0111\u01b0\u1ee3c s\u1ebd l\u1edbn h\u01a1n kh\u1ed1i l\u01b0\u1ee3ng th\u1ef1c c\u1ee7a v\u1eadt, d\u1eabn \u0111\u1ebfn sai s\u1ed1 khi tính kh\u1ed1i l\u01b0\u1ee3ng riêng theo công th\u1ee9c $D = \\frac{m}{V}$<\/span>\u200b.<\/p>","answer":"\u0110áp án \u0111úng là:<\/strong> D. C\u1ea3 A và B \u0111\u1ec1u \u0111úng. Gi\u1ea3i thích:<\/strong> V\u1eadt r\u1eafn không th\u1ea5m n\u01b0\u1edbc giúp \u0111\u1ea3m b\u1ea3o r\u1eb1ng khi th\u1ea3 vào bình, th\u1ec3 tích n\u01b0\u1edbc dâng lên ch\u1ec9 là th\u1ec3 tích c\u1ee7a v\u1eadt và kh\u1ed1i l\u01b0\u1ee3ng không b\u1ecb thay \u0111\u1ed5i do h\u1ea5p th\u1ee5 n\u01b0\u1edbc.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2025-02-14 08:13:32","option_type":"txt","len":3}]}