如图测未知电阻Rx的阻值：小亮所在的学习小组，在测定未知电阻Rx_爱下问搜题

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问题实验题

如图测未知电阻R_x的阻值：小亮所在的学习小组，在测定未知电阻R_x的实验中，手边只有一个未知电压的电源、一个阻值已知的定值电阻R₀、一块电流表、4个开关、一个待测电阻R_x和若干导线，缺少一块电压表，学习小组研究决定，只用现有器材，在不拆卸电流表的条件下，设计出实验电路图．经小组成员共同努力，采取巧用开关的办法，设计出了能满足上述要求的实验电路图．

（1）请你根据这个电路图，写出实验步骤：① _________ ；② _________ ．

（2）被测电阻的表达式R_x= _________ ．

（3）你对这个实验电路图的改进建议是 _________ ．

答案

（1） ①断开S₁、S₂、S₄，闭合S₃，测出R₀中的电流I₀；

②断开S₁、S₂、S₃，闭合S₄，测出R_x中的电流I_x

（2）R₀；

（3）去掉S₁、S₂．

完形填空

One of the most remarkable things about the human mind is our ability to imagine the future. In our minds we can see what has not yet happened. For example, while we are looking forward to 1._____a new place or country, we 2._____what it will be like. We predict( 预料) the habit people will eat, dress and act. Of course, we do not always predict things 3._____. Things are often very different from the way we 4._____them to be.
One of the 5._____ dreams in history is the dream of the German scientist, Kekule, who had been 6._____ to work out a very difficult problem in physics. He had studied and analyzed(分析) the problem from every angle(角度) for days, but there 7._____ to be no way of 8._____ out the answer. Then one night he went to bed and dreamed. When he 9._____ up, he realized that he knew the answer. He had solved the problem in his 10._____.
The hypnotist(催眠者) sat in the chair opposite him and spoke 11._____: I want you to concentrate on my voice. Think about 12._____. You know nothing but my voice. And as you pay attention to my voice, your 13._____ will get heavier. Soon you’ll be asleep.
You will hear my voice and understand my words, but your body will be asleep, your eyes are too heavy. You are almost asleep, and when you wake up you will 14._____ nothing.
You will forget everything. Now I am going to 15._____ slowly from one to five. One, two, three, four, five.

D．discovering

单项选择题

布图设计已经投入商业利用的，在申请布图设计登记之时，申请人应该提交含有该布图设计的（）。

A.文字资料

B.集成电路样品

C.设计原稿

D.布图设计图纸