F.4Physics(Transfer processes)

2009-09-13 12:45 am

Each questions below consists 2 statements. Decide whether each of the 2 statements is true or false. If both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option A-D according to the following.

A: 1st statement --- true , 2nd statement --- true (2nd statement is the explanation of the 1st statement)

B: 1st statement --- true , 2nd statement --- true (2nd statement is not the explanation of the 1st statement)

C: 1st statement --- true , 2nd statement --- false

D: 1st statement --- false , 2nd statement --- true

1. During conduction, the net transfer of heat stops when both bodies attain the same temperature. The internal energy of the resulting bodies becomes the same.

2. Hot objects can emit infra-red radiation of higher intensity than cold objects. Infra-red radiation can travel through vacuum.

3. Heat energy may be transferred by infra-red radiation through vacuum. Infra-red is a kind of electromagnetic waves.

4. Convection can take place in liquid and gas only. Liquid and gas obtain free electrons as energy carries.

更新1:

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!

回答 (2)

myisland8132

2009-09-13 2:33 am

✔ 最佳答案

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 是對的。熱幅射強度正比於溫度的4次方。
3 是對的。紅外線是電磁波的一種
4 是錯的。正常氣體何來自由電子?例如氫氣是H2。是由2個氫結合在一起的。

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[匿名]

2009-09-13 9:09 pm

Answer:
1.C
transfer process between two bodies by conduction stop when both kinetic enrgy are same, which do not relate to the internal energy(their states can be different).
2.B
"hot objects can emit infra-red radiation of higher intensity than cold objects" is correct because the hot oject should have higher energy the the cold object.(infra-red radiation is a kind of electromagnetic waves which only wave can carry energy.)
The second statement is also correct but it is not the explanation of the first statement.
3.A or B
Both statements are correct but they have indirect relationship.
4.C
As the position of particles in liquid or gas state are freely to move. The part which near the heating area have a lower density and rise.The colder part have a higher density which replace the space. It occurs a covection current.
As liquid and gas do not have any free electron(in metal only) ,statement two is incorrect.

參考: myself

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