问题 选择题

关于多普勒效应,以下说法正确的有(  ).

A.只有机械波才能产生多普勒效应

B.当波源和观测者都运动时就产生多普勒效应

C.产生多普勒效应的原因是波源的频率发生了变化

D.产生多普勒效应的原因是观测者接收到的频率发生了变化

答案

答案:D

多普勒效应是波动过程共有的特征,无论是机械波、电磁波还是光波都会发生多普勒效应.产生多普勒效应的原因是波源和观测者有相对运动,导致观测者接收到波的频率发生了变化,而波源的频率不变,故选项D正确,A、B、C错误.

阅读理解

Chen Guangbiao was born in Jiangsu in July,1968. He is the chairperson of a company in Jiangsu. Now he is one of China’s richest men and he has donated a great amount of money to charity projects. He says he will donate everything he has to charity after he dies.

When people are in need of help, he will appear at once. He helped people during the Wenchuan earthquake, the Yunnan earthquake and the Taiwan earthquake. He also gave a helping hand in Japan’s earthquake. He has built many Hope Primary Schools to support the education in poor areas.

He doesn’t do charity for honour. He wants to encourage more people to make contributions to charity. After announcing he would donate everything to charity after his death, many businesses, overseas(海外)Chinese people and common people encouraged by him have also promised to do something for charity.

As a philanthropist(慈善家),he is asked for help every day. Sometimes he gets very tired, but he has never stopped caring.

So far, he has received a lot of awards, including Pioneer of the Year, and National May Day Labour Medal(全国五一劳动奖章).He is considered as one of china’s top philanthropists.

小题1:The article is probably taken from _______.

A.a newspaper

B.a novel

C.a detective story

D.a science book小题2:He says he will donate _____ to charity after he dies.

A.nothing

B.some schools

C.everything he has

D.his whole company小题3: What does he do charity for?

A.He wants to do charity for money.

B.He wants to do charity for pleasure.

C.He wants to ask people to help him.

D.He wants to encourage more people to contribute to charity.小题4:Which of the following is NOT mentioned in the passage?

A.He is from Jiangsu.

B.He has visited many countries.

C.He has helped people in need.

D.He has got a lot of awards.小题5:Which do you think is the best title for the passage?

A.Earthquakes.

B.Hope Primary Schools.

C.Pioneer of the Year.

D.Philanthropist Chen Guangbiao

填空题