问题 选择题

一个闭合矩形线圈在匀强磁场中绕垂直于磁感线的轴匀速转动,产生的感应电流如图所示.由该图可得出的正确判断是(  )

A.0.01s时,线圈平面处于中性面位置

B.0.02s时,线圈平面与磁感线平行

C.该交变电流的频率为100Hz

D.1s内电流的方向变化50次

答案

A、由图象可知,0.01s时,感应电流为零,则感应电动势为零,磁通量最大,线圈平面处于中性面位置,故A正确;

B、由图象可知,0.02s时,感应电流为零,则感应电动势为零,磁通量最大,线圈平面处于中性面位置,故B错误;

C、由图象可知,T=0.02s,频率f=

1
T
=50Hz,故C错误;

D、1秒内完成50圈,一个周期内电流方向改变两次,所以线圈中感应电流的方向变化100次,故D错误.

故选:A.

阅读理解

阅读理解。

       Academy Awards The Academy Awards are the most prominent film award in the United States. The

Awards are granted by the Academy of Motion Picture Arts and Sciences. Academy Awards are nicknamed

"Oscars", which is also the nickname of the statuette. The name is said to have been born in 1931 when

Margaret Herrick saw the statuette on a table and said. "It looks just like my uncle Oscar!" 

      Berlin Film Festival One of the "A" festivals in Europe. The Berlin International Film Festival, also called

the "Berlinale", is held annually in February and started in 1951 after an initiative of the American, who

occupied part of the city after World War II. The jury always placed special emphasis on representing films

from all over the world, from the former Eastern Bloc Countries (东方阵营) as well as from Western

countries.The awards are called Golden and Silver Bears ( as the bear is the symbol of Berlin).

      Venice Film Festival The Venice Film Festival takes place every year in late August/early September on

the Lido in the historic Palazzo del Cinema, in Venice, Italy since 1932; its main award is the "Leond'Oro"

(Golden Lion). Recently, a new award has been added, the San Marco Award for the best film. 

      Cannes Film Festival The Cannes Film Festival is. a famous international film festival. It has been held

annually in Cannes, in the south of France, since 1946 with a few exceptions. Given massive media exposure,

the Festival is attended by many movie stars and is a popular venue for movie producers to launch their new

films and attempt to sell their works to the distributors who come from all over the globe.

      The most famous award given out at Carmes is the "Palme d'Or" (Golden Palm) for the best film; this is

sometimes shared by multiple films in one year.

1. Which award can be shared by multiple films in one year? [ ]

A. Golden Lion.

B. Golden Palm.

C. Academy Awards.

D. San Marco Award.

2. Which of the following statements about "Oscars" is NOT true?[ ]

A. It s the nickname of Academy Awards.

B. It's also the nickname of the statuette.

C. It got its name because Margaret said the statuette looked like her uncle.

D. It s an award in France.

3. Which award has the shortest history? [ ]

A. Golden Lion.

B. Golden Palm.

C. Academy Awards.

D. San Marco Award.

4. Which of the following best states the main idea of the passage? [ ]

A. An introduction to famous film festivals and film awards.

B. An advertisement for films and TV programs.

C. An introduction to the nicknames of famous film awards.

D. A guide of bow to attend famous film festivals.

单项选择题 B型题