如图所示,监测器测得同一声源发出的甲,乙两声音的特性如下表。甲乙相比( )
【考点】音调及音调与频率的关系,响度及响度与振幅的关系
【解析】【解答】A.声音的音调高低由频率大小决定;因为甲的频率大于乙的频率,所以甲音调高,故A错误;
B.声音的强弱就是声音的响度,因此乙声音的响度大,故B错误;
C.声音的响度由振幅决定,因为甲声音的响度小,所以甲声源的振幅小,故C错误;
D.频率表示物体振动的快慢;频率小,那么物体振动的慢,即每秒振动次数较少;因为乙的频率大于甲的频率,所以声源在发乙声音时每秒振动次数较少,故D正确。
故选D。
【分析】(1)声音的音调高低由频率大小决定,声音的强度就是响度,由物体的振幅决定;
(2)物体在1s内振动次数的多少叫频率。
如图所示,监测器测得同一声源发出的甲,乙两声音的特性如下表。甲乙相比( )
书面表达
初中生活即将结束,请你想一下,谁是你最喜欢的老师?他、她长什么样子?你 为什么喜欢他/她?
以My favorite Teacher为题,用英语写一篇短文,请根据要点进行描述,可以结合具体事例,也可以适当增加自己想写的内容。
要点:1. What does he/ she look like?
2. Why do you like him/her?
3. ......
注意:1.词数80-100
2.可适当增加细节及要点以外的内容,要求行文连贯;
3.文中不得出现真实姓名及学校名称。
阅读填词
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weight hungry was test eat see well going carefully all |
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A: Hello, Tom. Tomorrow is Sunday. Shall we go swimming?
B: . I am not feeling well.
A: ?
B: I have a headache. I think .
A: You are tired? Maybe you should take a rest.
B: . I'll have a good sleep this afternoon.
A: I hope you'll be better soon. And Let's go swimming next time.
B: All right. !
A: Bye
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根据中文提示完成单词,使句子完整、通顺。
This activity showed us the (重要性) of protecting our environment.
Boys and girls, help y to some fish.