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问题 计算题

为了测定液体的电阻率,工业上用一种称为“电导仪”的仪器,其中一个关键部件如图所示.A､B是两片面积为1 cm2的正方形铂片,间距d="1" cm,把它们浸没在待测液体中.若通过两根引线加上一定的电压U="6" V时,测出电流I=1μA,则这种液体的电阻率为多少?

答案

6×104 Ω·m

由电阻公式R=ρ,变形可得

ρ==6×104 Ω·m.

阅读理解

阅读理解。

     The students were having their chemistry class. Miss Li was telling the children what water was like.

After that, she asked her students, "What's water?" No one spoke for a few minutes. Miss Li asked again. "Why don't you answer my question? Didn't I tell you what water is like?"

     Just then a boy put up his hand and said, "Miss Li, you told us that water has no color and no smell.

But where can we find Such kind of water? The water in the river behind my house is always black and it

has a bad smell. " Most of the children agreed with him.

     "I am sorry, children," said the teacher."Our water is getting dirtier and dirtier. That's a problem. "

1. The students were having their _______ class.

A. English                  

B. Chinese

C. chemistry                  

D. math

2. Miss Li was telling the children what          __was like.

A. water                    

B. air

C. earth                      

D. weather

3. A boy said, "The water in the river behind my house is always      ____  .

A. whit e                    

B. black

C. clean                    

D. clear

4. Most of the children _       __  the boy.

A. agreed with            

B. wrote to

C. heard from              

D. sent for

5.The water in the river has color and smell because it is getting         ___.

A. more and more        

B. less and less

C. cleaner and cleaner      

D. dirtier and dirtier
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单项选择题

决定施工起点的因素不包括（）

A.劳动力需求计划

B.保证质量的要求

C.建设单位的喜好

D.施工管理人员的喜好
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