问题 选择题

小强同学在探究串联电路电流规律的实验中,按下图连接好了电路,闭合开关S后,观察实验,两灯均不发光。为检测出电路故障,他做了以下操作:将电压表接到b、c两点,观察电压表、电流表均无示数。将电压表接到a、b两点,观察电压表有明显示数,而电流表示数几乎为零,则电路故障可能是

A.灯L2断路  

B.灯L2短路 

C.电流表烧坏了

D.灯L1断路

答案

答案:A

题目分析:在串联电路中,两灯都不发光,应是断路故障,当把电压表接到a、b两点时,电压表有示数,说明通过电压表有电流,电流的路径是:电源正极→开关→电流表→电压表→L1→电源负极,这一回路中的所以器材都是完好的,所以是灯L2断路,至于电流表无示数,是由于电压表的内阻太大,导致电路中的电流太小,不能使电流表的指针偏转造成的。

阅读理解

Ole Bull was a very famous violinist from Norway. He really liked to play the violin. But his father thought that playing the violin was not useful. So his father sent him to university to study. However, playing the violin was his dream. He didn’t want to give up his dream. So he left university before he finished his studies and spent all his time and energy practicing the violin. Unfortunately, his violin teacher was not very good. So when it was time for him to start his concert tour, he still couldn’t play the violin very well.

Therefore, a Milan newspaper critic1 criticized him and said that he was an untrained violinist. The critic said, “If he is gold, he is not ready to shine2 yet.

When facing this kind of problem, some people may become very angry and some people try to learn from it. Fortunately, Ole Bull belonged to the second group. He went to the newspaper office and found the critic. Instead of being angry, he talked about his mistakes with the man and listened to the man’s advice.

After he met the critic, he gave up the rest of his concerts. Then he went back to practice the violin with the help of good teachers. In the end, he got great success when he was only 26. He also became one of the most famous violinists in the world.

小题1:Why didn’t Ole Bull’s father like him to play the piano?

A.Because he thought playing the violin was useless.

B.Because his father thought playing the violin would cost lots of money.

C.Because his father thought he couldn’t play the violin well.

D.Because his father thought he couldn’t make his dream come true.小题2:What does the underlined part "If he is gold, he is not ready to shine yet." mean?

A.Gold always shines no matter where it is.

B.He is an excellent violinist.

C.He doesn’t play the violin very well.

D.If he sells gold, he will make a lot of money.小题3:What was Ole Bull’s attitude towards the critic’s article?

A.Angry.

B.Excited.

C.Modest.

D.Worried.小题4:Which of the following is NOT true according to the passage?

A.Without a good teacher, one can’t succeed.

B.The critic’s advice helped Ole Bull a lot.

C.Ole Bull got success after many years’ hard practice at last.

D.The critic helped Ole Bull find a famous teacher.小题5:What can we learn from the passage?

A.Becoming a violinist can make a lot of money.

B.When we meet problems, we should learn to face them.

C.Old Bull was a famous American pianist.

D.You can be famous easily if you play the violin.

单项选择题 配伍题