问题 探究题

在做“决定电阻大小的因素”实验时,需要在电压相同的条件下,比较通过不同导线的电流,发现决定电阻大小的因素.下表是几种实验用导线的参数

(1)为研究电阻与导体材料有关,应在上表中选用导线C和导线 _________

(2)为研究电阻与导体长度有关,应在上表中选用导线C和导线 _________

(3)为研究电阻与导体横截面积有关,应在上表中选用导线A和导线 _________

(4)下表列出了一些材料制成的长1m、横截面积为1mm2的导线在20Ω时的电阻值.根据表中数据回答:假如让你架设一条输电线路,在铝线和铁线之间,你应选用_________;假如要选用一根金属丝来做滑动变阻器的电阻丝,在铁丝和锰铜丝之间,你应选用_________.并写出你选择的理由:_________

答案

(1)F

(2)G

(3)D

(4)铝线;锰铜丝;选用输电线时,应该是电阻较小的较好,选用滑动变阻器的电阻丝时,应该是电阻较大的更好.

阅读理解

阅读理解。

     Years ago, when I started looking for my first job, wise advisers advised,  "Barbara, be enthusiastic!

Enthusiasm will take you further than any amount of experience." How right they were!

     "Nothing great was ever done without enthusiasm," wrote Ralph Waldo Emerson. It is the paste (浆

糊) that helps you hang in there when the things get tough. It is the inner voice that tells you, "I can do it!" when others shout, "No, you can't!" It took years and years for the early work of Barbara McClintock, a

geneticist who won the 1983 Nobel Prize in medicine, to be generally accepted. Yet she didn't stop

working on her experiments.

     We are all born with wide-eyed, enthusiastic wonder and it is the childlike wonder that gives

enthusiastic people such youthful air, whatever their age. At 90, cellist Pablo Casals would start his day

by playing the cello (大提琴). As the music flowed through his fingers, his shoulders would straighten and

joy would reappear in his eyes. As writer and poet Samuel Ullman once wrote, "Years wrinkle (起皱纹)

the skin, but to give up enthusiasm wrinkles the soul."

     Enthusiastic people also love what they do, not considering money or title or power. Patricia Mellratl,

a retired director in Kansas City, was once asked where she got her enthusiasm. She replied, "My father,

long ago, told me, 'I never made any money until I stopped working for it.'"

     We can't afford to waste tears on "might-have-been". We need to turn the tears into sweat (汗水)as

we go after "what-can-be". We need to live each moment whole-heartedly, with all our senses finding

pleasure in the sweet of a backyard garden, the simple picture of a six-year-old, and the beauty of a

rainbow.

1. What is the passage mainly talking about?

A. Enthusiasm is more important than experience.

B. Enthusiasm can give people more success and fame

C. Enthusiastic people will never get old

D. Enthusiasm can make you succeed and enjoy life.

2. We can infer that enthusiasm is more important for a person especially when __________.

A. he is in trouble          

B. he is getting old

C. he can do what he love  

D. he has succeeded

3. The author mentions Pablo Casals in the third paragraph to show that ______.  

A. enthusiasm can make people feel young

B. music can arouse people's enthusiasm

C. enthusiasm can give people inspiration needed to succeed

D. enthusiasm can keep people healthy

4. How many examples are referred in the passage to show the importance of enthusiasm?

A. Three      

B. Four      

C. Five      

D. Six

5. Which proverb may the writer agree with according to the last paragraph? 

A. A good beginning makes a good ending    

B. Don't cry over the spoiled milk

C. All work and no play makes Jack a dull boy  

D. Love me, love my dog  

问答题 简答题