试题与答案

图甲是小明探究电流跟电压关系的电路图。若电源电压保持不变,当开关S闭合后,将滑动

题型:探究题

题目:

图甲是小明探究电流跟电压关系的电路图。若电源电压保持不变,当开关S闭合后,将滑动变阻器的滑片P从a端移到b端,电流表和电压表的示数变化关系如图乙所示。

(1)由图像可知:通过R0的电流与R0两端的电压成________,R0的最大功率P0=________W,滑动变阻器的最大阻值R=_______Ω。

(2)实验操作中滑片至少要移动_______次,目的是____________________。

(3)在完成以上实验后,小明又测额定电压为2.5V的小灯泡的电流和电压,下列图像正确的是[ ]

A.

B.

C.

D.

答案:

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参考答案:B解析: 如下图所示,两条输水管通过连通管被分为n段,设各段输水管的摩阻均为 S。图(a)为正常工作的情况,输水量为设计水量Q;图(b)为某一段损坏时的情况,输水量为事故水量Qa。各段输水管的流量标...

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题型:阅读理解

阅读理解

     Good afternoon, ladies and gentlemen. My topic is "__________".

     Now in the 21st century, advertising is more and more important for people. Why? I think it is because through advertising, people, especially the businessmen, can introduce their products to the people all over the world. Because of this, many companies spend a lot of money on advertising. As we all know, there are many advertisements which are very interesting and popular. For example, Michael Jordan made an interesting advertisement for Nike. From this you can see how the companies make their products known to the world.

     People can make a lot of money through advertising. It is known that many famous singers and movie stars make money in this way. However, I don't think this is a good way for them to make money, because they are not the professional(职业的) advertisers, especially those who advertise in medicine advertisements.

     Nowadays, advertising not only means making the products known, but also means making ourselves known to people around us. Living today, we have to make people believe in us if we want to do important jobs. But how can this be done? We should first let other people know our good side: the good habits and abilities we have. In short, we should always remember to advertise ourselves to others. As I said before, advertising is not only important for companies but also for everyone, for all human beings. This is the most interesting thing about advertising.

1. The best topic to fill in the line in the first paragraph is "__________".

A. The Importance of Advertising

B. Making Money through Advertising

C. Advertising Ourselves

D. Advice on Advertisements

2. This passage may be a(an) __________.

A. advertisement

B. story

C. speech

D. report

3. According to the passage, which of the following is NOT right?

A. Many companies are willing to spend money on advertising.

B. Advertising can make some people rich.

C. People can introduce their products through advertisements.

D. Advertising is not necessary for anyone.

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