问题 单项选择题

声音从声源发出,在均匀无限大的空气中传播的过程中,( )。

A.声波的波速不断减小
B.声波的波长不断减小
C.声波的振幅不断减小
D.声波的频率不断减小

答案

参考答案:C

解析: 波速只与介质有关,所以不变,频率只与波源有关,也不发生变化,根据u=λv可知,波长也不发生变化,声音在媒介中传递时能量逐渐减小,能量与振幅的平方成正比,所以振幅减弱。

单项选择题 A1型题
阅读理解

阅读理解。

Fair Way

      The Westborough High School golf team had taken the official photos with the state prize. The other

teams, disappointed, were on the bus heading home. And then Westborough instructor Greg Rota noticed

something wrong on one of the score cards. A 9 had been recorded as A 7. They were not the state prize

winner; Woburn High had won. "No one would have known," said Woburn's instructor, Bob Doran. For

Rota, it wasn't a difficult decision:"The prize wasn't ours to take."

Coin Stars

     "College students are lazy, but they also want to help," says University of Pennsylvania graduate Dana

Hork. So she made it easy, placing cups in rooms where students could leave their spare coins, and handing

out cups to first-year students to keep in their homes. Her "Change for Change" effort has collected $40,000

for charities, which were decided upon by students.

Never Forgotten

     A school in Massachusetts received a $9.5 million check from Jacques LeBermuth. But it took officials

several days of digging to discover his connection to the school. Records showed the LeBermuth came from

Belgium and studied in the school in the 1920s. When his family fell on hard times, he was offered free room

and board. LeBermuth became a trader, owned shares of AT&T and lived off the earnings until he died, at

age 89.

1. What did Greg Rota probably do in the end? [ ]

A. Took photos of Doran.

B. Had a meeting with Doran.

C. Returned the prize to the organizer.

D. Apologized to Woburn High School.

2. Greg Rota's decision shows that he was _____. [ ]

A. honest

B. polite

C. careful

D. friendly

3. The underlined word "Change" in the second paragraph means _____. [ ]

A. Idea

B. Decision

C. Cups

D. Coins

4. What did the school officials do after receiving the check from Mr. LeBermuth?[ ]

A. They tried to find out why he gave them the money.

B. They went to Belgium to pay their respects to him.

C. They dug out the records that were buried underground.

D. They decided to offer their students free room and board.

5. Jacques LeBermuth gave the money to the school because _____. [ ]

A. the school asked for it

B. he had no need for that much money

C. the school had helped him in the past

D. he wanted to be remembered by the students