问题 实验题

在“测定金属丝的电阻率”的实验中,待测合金电阻丝阻值Rx约为4Ω。

①用游标卡尺测量电阻丝的长度L。测量结果如图所示,图中读数为L =        mm。

用螺旋测微器测量电阻丝的直径d。测量结果如图所示,图中读数为d =         mm。                             

②为了测量电阻丝的电阻R,除了导线和开关S外,

还有以下一些器材可供选择:

电压表V,量程3V,内阻约3kΩ

电流表A1,量程0.6A,内阻约0.2Ω

电流表A2,量程100μA,内阻约2000Ω

滑动变阻器R1,0~1750Ω,额定电流0.3A

滑动变阻器R2,0~50Ω,额定电流1A

电源E(电动势为3V,内阻约为1.2Ω)

为了调节方便,测量准确,实验中应选用电流表________,滑动变阻器_________,(填器材的符号)

③在所给的实物图中画出连线,接成测量电路图。

④若电压表测量值为U,电流表测量值为I,用测量的物理量表示计算材料电阻率的公

式是ρ =                          

答案

① 54.5mm   0.855mm   

②A1    R2 

③如图(电流表要外接,滑线变阻器要分压连接)

①游标卡尺:

螺旋测微器:

②应选用阻值太大,操作起来不方便,当选用时,电路中最小电流大概为,所以选用

③如图(电流表要外接,滑线变阻器要分压连接)

④根据公式,得,所以

阅读理解

阅读理解。

     The human nose has given to the language of the world many interesting expressions. Of course, this

is not surprising. Without the nose, We could not breathe or smell. It is the part of the face that gives a

person special character. Cyrano de Bergerac said that a large nose showed a great man-courageous, manly,

and wise.

     A famous woman poet wished that she had two noses to smell a rose! Blaise Pascal made an interesting

remark about Cleopatra's nose. If it had been shorter, he said, it would have changed the whole face of the

world!

     Man's nose has had an important role in his imagination. Man has referred to the nose in many ways to

express his emotions. Expressions dealing with the nose refer to human's weakness, anger, pride, jealousy

and revenge (报复).

     In English there are a number of phrases about the nose. For example, to hold up one's nose expresses

a basic human feeling-pride. People can hold up their noses at people, things, and places.

     The phrase, to be led around by the nose, shows man's weakness. A person who is led around by the

nose lets other people control him. On the other hand, a person who follows his nose lets his instinct (本能)

guide him.

      There are a number of others. However, it should be as plain as the nose on your face that the nose is

more than an organ for breathing and smelling.

1. The passage is about ______.

A. an organ, with which people can breathe and smell

B. the nose, which gives different and useful expressions

C. the nose giving a person special character

D. the interesting remarks about the nose made by some people

2. From the passage we know _______.

A. "Cleopatra's nose" changed the whole face of the world indeed

B. Cleopatra had a strong will to change the whole look of the world

C. Cleopatra's nose was not short

D. Cleopatra hoped that people would change the whole face of the world

3. The nose expresses ______.

A. some human weakness or other

B. people's shortcomings

C. people's different emotions

D. human feelings in bad sense

4. A person who follows his nose _____.

A. won't take others' advice

B. is easily controlled by others

C. is weak-minded

D. will let his will guide him

多项选择题