? asked in 科學及數學其他 - 科學 · 1 decade ago

F.4 Physics Transfer Processes

1. Which of the following statements is/are correct?

(1) Conduction is the transfer of heat from objects with higher internal energy to objects with lower internal energy.

(2) During Convection, hot air rises because it possess higher internal energy than cool air.

(3) Internal energy is a measure of the extent of molecular motions and interactions.

A (2) only

B (3) only

C (1) AND (2) only

D (1) and (3) only

2. No wind will be generated by an electric fan in vacuum because:

A. conduction of the movement of moleculars is poor

B. there is no air

C. movement of molecules in vacuum is limited even when a fan is turned on.

D. radiation comes from hot objects only but not from cold objects.

Please explain for every questions. I will make you be the best answer if you explain in the best way. (please do not copy others' answer) Thank you!

1 Answer

  • 1 decade ago
    Favorite Answer

    1 是錯的。因為內能和物體的大小有關。而熱則會由高溫物體流向低溫物體。所以當您倒一杯100度的水入湖中﹐整個湖的內能固然高過100度的水﹐但熱會由100度的水流向湖水。

    2 是錯的。熱空氣上升是因為其分子運動較快﹐體積增大導致密度下降。

    3 是對的。內能是分子動能和分子間勢能的總和

    2 B 因為真空即是沒有空氣﹐沒有氣壓差從而沒有伯努利定律是也。

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