Two objects ares heated by two heaters of the same power for the same time. Which of the following are true?
(1) The same amount of heat is transferred to the two objects.
(2) The two objects have the same gain in internal energy
(3) The two objects have the same rise in temperature
Ans : (1) and (2) only
Plz explain why (2) is true and (3) is false. THX!!
CE level Phy Heat Qu.
2008-04-15 5:35 am
回答 (4)
2008-04-15 5:45 am
✔ 最佳答案
(2) Internal energy means the total amount of kinetic energy and potential energy . Heat is used to increase the kinetic energy and potential energy of the molecules , so it is true .(3) The two objects may have different specific heat capacity , so the rate of temperature may rise in different rate . so it is wrong .
參考: Me
2008-04-15 8:25 am
Since the heater power and time of heating are the same, the amount of energy given to both objects (equal to power x time) should be the same (assuming no heat loss to the surroundings).
(1) and (2) refer to the same:
Heat means the work done by the heater on the object in form of internal energy.
(1) and (2) refer to the same:
Heat means the work done by the heater on the object in form of internal energy.
2008-04-15 6:18 am
唔係PAST PAPER 黎
係KEN CHAN D EX.
2008-04-14 23:44:19 補充：
我都係咁諗...
但佢有幾條都一樣問法
個答案都係咁
希望有高手可以解答下
係KEN CHAN D EX.
2008-04-14 23:44:19 補充：
我都係咁諗...
但佢有幾條都一樣問法
個答案都係咁
希望有高手可以解答下
2008-04-15 6:14 am
想問你lee題係邊年ka? 我都覺得(2)有d問題。
2008-04-14 23:43:03 補充：
oh, 咁可能答案有錯啦!
internal energy = PE + KE
既然(3)係錯嘅, 即係two objects may have different rise in temperature, 咁KE gain 都未必唔同啦 ; 就算佢地轉緊state, 咁PE gain都可以唔同, 正如你所講[可能唔同MASS ],
於是gain in internal energy應該都未必同。個人意見, 答案只有(1)。
2008-04-15 00:43:05 補充：
明白了, 多謝大哥^^
2008-04-14 23:43:03 補充：
oh, 咁可能答案有錯啦!
internal energy = PE + KE
既然(3)係錯嘅, 即係two objects may have different rise in temperature, 咁KE gain 都未必唔同啦 ; 就算佢地轉緊state, 咁PE gain都可以唔同, 正如你所講[可能唔同MASS ],
於是gain in internal energy應該都未必同。個人意見, 答案只有(1)。
2008-04-15 00:43:05 補充：
明白了, 多謝大哥^^
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