问题 选择题

如图所示,封有一定质量气体的烧瓶与U形压强计连接,用此装置研究气体体积不变时压强与温度的关系。烧瓶浸在冰水混合物中时,可动管A和固定管B中的水银面刚好相平。现把烧瓶浸入热水中,观察到的现象和正确的操作是(   )

(A)B管水银面下降,须记下A、B两管中水银面的高度差

(B)B管水银面下降,应向上适当移动A管

(C)最终调整到A、B两管中水银面相平

(D)最终使A管中水银面回复到管壁原来位置

答案

答案:B

因为用此装置研究气体体积不变时压强与温度的关系,故应保证实验过程中体积不变,B正确。

问答题
阅读理解

阅读理解。

     Skin diving (潜泳) is a new sport today. This sport takes you into a wonderful new world. It is like a

 visit to the moon! When you are under water, it is easy for you to climb big rocks because you are no

 longer heavy.

     Here, under water, everything is blue and green. During the day, there is enough light. When fish swim

 nearby, you can catch them with your hands.

     When you have tanks (罐子) of air on your back you can stay in deep water for a long time. But you

 must be careful.

     To catch the fish is one of the most interesting parts of this sport. On the other hand, you can clean the

 ships without taking them out of water. You can get many things from the deep sea.

     Now you can see that skin diving is both useful and interesting.

1. Skin diving can take you to ______.

    A. the moon

    B. mountains

    C. the sun

    D. the deep sea

2. You can climb big rocks under water because ______.

    A. you are strong

    B. the fish can help you

    C. you are not as heavy as on the land

    D. there is a lot of light

3. A skin diver ______ under water in the day.

    A. can see everything clearly

    B. can't see anything clearly

    C. can see nothing

    D. can see only fishes

4. With a tank of air on your back, you can______ .

    A. catch fish very easily

    B. stay under water for a long time

    C. be in safe place

    D. have more fun

5. Which of these sentences is NOT true?

    A. Skin diving is a new sport.

    B. Skin diving is like visiting the moon.

    C. The only use of skin diving is to have more fun.

    D. Skin diving is both interesting and useful.