PHY的3條問題 - Ans.fyi 參考答案

PHY的3條問題

2007-01-02 6:37 am

tom prepares 2cups of hot water a and b. they are of same mass and same temperature.he puts cup a on a table and cip b into a refrigerator.after 10mins,he records the final temperature of the 2cups of water.

A)does the temperature of each cup of water drop?explain this in terms of energy transfer.

更新1:

B)which cup of water is cooler?explain this terms of the temperature difference and the rate of energy transfer. C)an ice cream bar is placed on the table.explain why it melts afterwards.suggest a method to make it freeze again.

回答 (1)

Hobson

2007-01-02 7:10 am

✔ 最佳答案

A) Temperature of Cup A will remain unchange. and Temperature of Cup B will drop. Heat is transfer from higher temperatur to lower temperature. In this experiment, Cup A will remain as room temperature. Cup B will drop its temperature because of the lower temperature inside refrigerator.

B) Cup B is cooler. Because the heat difference of cupA is much less than that of cup B.
according to the equal M * C * delta T. M and C are constant, so energy transfer from cup B is larger than cup A.

C) Because the heat energy from surrounding is transfering to the ice-cram, the internal energy of the ice cream increases that increase the temperature of the ice cream. We may put it in the refrigerator again.

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