问题 计算题

如图,一根粗细均匀、内壁光滑、竖直放置的玻璃管下端密封,上端封闭但留有一抽气孔。管内下部被活塞封住一定量的气体(可视为理想气体),气体温度为T1。开始时,活塞上方的气体的压强为p0,活塞上方玻璃管的容积为2.6V1,活塞下方气体的体积为V1,活塞因重力而产生的压强为0.5p0。缓慢将活塞上方抽成真空并密封。整个抽气过程中管内气体温度始终保持不变。然后将密封的气体缓慢加热。求:

(1)活塞刚碰到玻璃管顶部时气体的温度;

(2)当气体温度达到1.8Tl时气体的压强。

答案

解:(1)抽气过程为等温过程,活塞上面抽成真空时,下面气体的压强为0.5p0,体积为V

依题意,由玻意耳定律得(p0+0.5p0)V1=0.5p0V

此后,气体等压膨胀,设活塞碰到玻璃管顶部时气体的温度是Tˊ

由盖·吕萨克定律得

由上两式得:Tˊ=1.2T1

(2)活塞碰到顶部后的过程是等容升温过程

由查理定律得

式中p2是气体温度达到1.8T1时气体的压强

由上式得:p2=0.75p0

阅读理解

阅读理解

Dear Mum,

       I didn't think you understand my life, You think I should be studying all the time. I know you want me

to find a good job when I grow up, but I would like to have a wonderful time, too. You never think about

fun things for me to do like music, sports. Two days ago, when I was watching a football game on TV, you asked me to stop and do my homework. After finishing my homework, still I wasn't allowed to read my

football magazines. You said I had to go to bed early. That was bad enough, but yesterday was the worst day. I bought some computer games, and put them in my bag so that you wouldn't see them. I told you I

had to do my homework first. I know it was wrong to lie to you, but you told me that Dad would talk to

me later. Mum, I didn't quite like what you did to me! I really love you, Mum, but I wish you could try not to be so hard on me.

                                                                                                                                                    Love,

                                                                                                                                                    Bob

1. Bob's mother wants him             when he grows up.        

A. to be a teacher                

B. to find a good job        

C. to work in a big city            

D. to become a football star

2.          is Bob's favorite sport.        

A. Football        

B. Volleyball        

C. Basketball        

D. Baseball

3. Bob's mother asked him           .        

A. to watch TV                                  

B. to do sports        

C. to play computer games                  

D. to study all the time

4. Why did Bob put the computer games in the bag? Because           .          

A. he didn't like them          

B. he played them many times          

C. he wouldn't like his mother to find them          

D. there was nothing wrong with them

5. We know from the letter that           .          

A. Bob lives a very happy life          

B. Bob hates his mother            

C. Bob wishes to study all the time            

D. Bob's mum is very strict with him

填空题