试题与答案

简述从电能和热的观点分析电弧内部的基本矛盾，怎样才能熄灭电弧？

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题型：问答题 简答题

题目：

简述从电能和热的观点分析电弧内部的基本矛盾，怎样才能熄灭电弧？

答案：

参考答案：

在电弧中不仅存在着中性质点的游离过程，同时也存在着带电质点相互碰撞，交换多余能量，形成中性质点的去游离过程。

若采取措施，使电弧中的去游离过程大于游离过程，使电弧中的中性质点增加，带电质点减少，达到一定程度时，触头间隙由良好的导电状态，就会变为绝缘状态，而使电弧熄灭。

考点：动力与电气工程电器学电器学题库
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题型：阅读理解

阅读理解。

     The influence of America is increasing in my country. Spanish people drink Coca Cola,

wear blue jeans, watch Hollywood movies, listen to American music, and eat fast food, and

they do these things every day.

    I think that American movies are a good way to spread American culture because people

are often influenced by what they see in the movies. Most of the programs and documentaries

(纪录片) we watch on TV are from America, and most of the movies we go to see are made

in Hollywood.

    In the last few years, the government has tried to protect the Spanish movies. Now, in our

cinemas, at least twenty percent of the movies which are shown must be from Spain or from

other countries in Europe.

    American culture is a part of Spanish life now. It's certain that many things from America

are as much a part of people's lives as Spanish things. For example, Coca Cola is as familiar

to everybody as any typical Spanish product. I've known about Coca Cola for my whole life.

    However, it's different with Western fast food. For example, I don't think McDonald's is as

successful in Spain as it is in other countries. In my opinion, one of the reasons may be the

lifestyle of the Spanish people. The Spanish people normally eat at home.

    On the other hand, maybe McDonald's hamburgers will eventually replace the famous

Spanish tapas. It's true that in every city in Spain you can find a McDonald's, and it is more

popular among the Spanish children than among the adults. In any case, it's obvious that

American culture is becoming more and more a part of our lives every day.

1. From the first paragraph we can know that ____.

A. the influence of America on Spain can be found everywhere

B. most Spanish people don't like to listen to their own music

C. fast food spreads from Spain to the United States

D. some Spanish actors go to America to improve their acting skills

2. Why did the government set some rules for the films shown in Spain?______

A. To protect foreign culture in Spain.

B. To earn more money from Spanish films.

C. To limit the number of foreign movies.

D. To unite the European Community.

3. Why does the author think that McDonald's is not as successful as it is in other countries? ______

A. Its fast food contains too much fat.

B. He thinks it is unhealthy.

C. Spanish people seldom eat out.

D. Spanish adults don't like its fast food.
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