问题 实验题

在图所示的实验装置中,用棉线将铜棒ab悬挂于磁铁N、S极之间,铜棒的两端通过导线连接到灵敏电流计上。当铜棒向左运动时,电流计的指针       (选填“偏转”或“不偏转”);该装置可将      能转化为电能。

答案

偏转,机械 (动能)

题目分析:闭合电路的一部分导体在磁场中做切割磁感线运动,即电磁感应现象,所以有感应电流产生.该装置可将机械能转化为电能.

点评:主要考查学生对发电机原理,即电磁感应现象的了解和掌握.是一道基础题.

阅读理解

阅读理解。

    Miss Gogers taught physics in a New York school. Last month she explained to one of her classes about

sound, and she decided to test them to see how successful she had been in her explanation. She said to them,

"Now I have a brother in Los Angeles. If I was calling him on the phone and at the same time you were 75

feet away, listening to me from across the street, which of you would hear what I said earlier, my brother or

you and for what reason?"

    Tom at once answered, "Your brother. Because electricity travels faster than sound waves." "That's every

good," Miss Gogers answered; but then one of the girls raised her hand, and Miss Gogers said. "Yes, Kate."

    "I disagree," Kate said. "Your brother would hear you earlier because when it's 11 o'clock here it's only

8 o'clock in Los Angeles."

1. Miss Gogers was teaching her class _____. [ ]

A. how to telephone

B. about electricity

C. about time zone (时区)

D. about sound

2. Miss Gogers raised this question because she wanted to know whether _____. [ ]

A. it was easy to phone to Los Angeles   

B. her student could hear her from 75 feet away

C. her students had grasped her lesson   

D. sound waves were slower than electricity

3. Tom thought that electricity was _____. [ ]

A. slower than sound waves  

B. faster than sound waves

C. not so fast as sound waves   

D. as fast as sound waves

4. Whose answer do you think is correct according to the law of physics? [ ]

A. Tom's  

B. Kate's   

C. Bath A and B   

D. Neither A nor B

填空题