首页
登录
职称英语
[originaltext] Objects that are vibrating make sounds. Rhythmic sound vibrat
[originaltext] Objects that are vibrating make sounds. Rhythmic sound vibrat
游客
2023-08-21
59
管理
问题
Objects that are vibrating make sounds. Rhythmic sound vibrations produce sound waves which travel in every direction. The frequency of a sound is the number of waves that pass a given point each second.The more rapidly an object vibrates, the greater the frequency of sound it makes. Frequency is measured in hertz. One hertz equals one sound wave per second. The frequency of sound determines the degree of highness or lowness of the sound. A high-pitched sound has a higher frequency than a low-pitched sound.Humans hear sounds that have frequencies from about 20 hertz to 20,000 hertz. Sound with a frequency higher than 20,000 hertz is called ultrasound which is too high-pitched for humans to hear. However, many animals can hear ultrasound. Bats can hear higher sounds than any other animal. Some can hear up to 210,000 hertz. Bats send out lots of high-pitched squeaks and then listen to the echoes bouncing off things like insects. The shorter the time interval between the squeak and the echo, the closer they are to the insect. Using sound to find or "see" things is called echolocation. Another animal that uses ultrasound is the dolphin. Dolphins can hear sounds up to about 150,000 hertz. Dolphins use sound waves to find food underwater.They make clicking sounds that hit whatever is around them and then bounce back to the dolphins. Dolphins can send as many as 2,000 clicks per second. Dolphins’ ultrasound ability is so sensitive that they can detect small fish from 10 feet away.
19. What is the relationship between the vibration of an object and the frequency of its sound?
20. What sounds can humans hear?
21. According to the speaker, what is the phenomenon of echolocation?
选项
A、A bat caught the insect in midair and ate it.
B、Dolphin’s clicking sounds bounced off the fish and back to it.
C、A person heard an echo when he shouted into the valley.
D、A dog heard his owner’s whistle because he used ultrasound.
答案
B
解析
细节题。文中提到,用声音来找或看东西被称为“回声定位法”。之后,短文以海豚为例说明“回声定位法”:海豚会发出尖利的声音,这种声音会撞击到它周围的任何物体,然后通过声波形式再传回到海豚处。通过这种方法,海豚可以找到离自己10英尺以内的小鱼。蝙蝠只是利用回声定位原理“找到”食物,但并非caught或ate,所以可排除强干扰项A。
转载请注明原文地址:https://tihaiku.com/zcyy/2945578.html
相关试题推荐
[originaltext]M:Hi,Mary.Comein.W:Uh,yeah,Istoppedbytoseeifyouare
[originaltext]M:Hey,Sally.I’mthinkingaboutgoingtoGermanythissummer,a
[originaltext]M:Hey,Sally.I’mthinkingaboutgoingtoGermanythissummer,a
[originaltext]W:Doyouwantmetoexplainthesequestionsbeforemeexam?M:
[originaltext]W:Doyouwantmetoexplainthesequestionsbeforemeexam?M:
[originaltext]MySpace,thesocialnetworkingwebsite,isdifferentfromoth
[originaltext]MySpace,thesocialnetworkingwebsite,isdifferentfromoth
[originaltext]I’dliketosharewithyoutodaymyexperiencewithanewapp
[originaltext]I’dliketosharewithyoutodaymyexperiencewithanewapp
[originaltext]I’dliketosharewithyoutodaymyexperiencewithanewapp
随机试题
Whathappensduringthenaturalgrowthofatreeeachyear?[originaltext]Du
Everyyear,theNobelPrizeisgiventooutstandingworkinsixfields:phys
甲喝醉后在家耍酒疯,随手将笔记本电脑从15楼扔出窗外,砸中在小区散步的居民王某,
下列关于TCP/IP协议的描述中正确的有()。A.lP层可提供面向连接的服务和无
提出,文章“乃经国之大业,不朽之盛事”的人是()A.曹操 B.曹丕 C.陆机
下列谱例中的低声部使用了哪种复调模仿手法?() A.倒影模仿 B.扩
制备黑膏药常选用的植物油是A.菜籽油B.大豆油C.花生油D.麻油E.棉籽油
下列教育家中,最早明确提出教育学的科学性问题的是( )A.裴斯泰洛齐 B.赫
王某对县民政局的决定不服向法院提起行政诉讼,县民政局向法院提供了由民政部制定的规
对卫生问题解决程度或达到计划预期目标的实际程度进行的评价属于A.效果评价 B.
最新回复
(
0
)