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
2024-04-15
30
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/3556755.html
相关试题推荐
[originaltext]AmericanvisitorstoEasternAsiaareoftensurprisedandpuz
[originaltext]InBritainthebiggestnumberofworkingforeignerscomesfro
[originaltext]Thefamilyischanging.Inthepast,grandparents,parents,a
[originaltext]M:I’msotired,Ican’tseestraight.W:You’vebeentiredalot
[originaltext]M:I’msotired,Ican’tseestraight.W:You’vebeentiredalot
[originaltext]W:Haveyouevervisitedaredwoodforest?Irecentlyhadachanc
[originaltext]W:Haveyouevervisitedaredwoodforest?Irecentlyhadachanc
[originaltext]W:Haveyouevervisitedaredwoodforest?Irecentlyhadachanc
[originaltext]M:I’mlookingforanunfurnishedtwo-bedroomapartment,butall
[originaltext]M:I’mlookingforanunfurnishedtwo-bedroomapartment,butall
随机试题
______issouthern-mostcapitalcityintheworld.A、AucklandB、CanberraC、Welling
StoryTellingI.StatusofstorytellingA.Inthe
Iboughtaquartofmilkandsix______atthemarket.A、corn’searsB、earsofco
WhatwillYahoo’shomepagebelikeafterredesigning?Itwillprovidemorespace
Smith骨折的典型移位是A.近侧端向背侧移位 B.远侧端向掌侧、尺侧移位
某高校教师非常注重教育教学方法,善于发现各个学生身上的特长,做到因势利导。这说明
下列选项中,属于奖励信息应包括的内容的有()。 Ⅰ.受奖励单位或个人Ⅱ.表彰
手厥阴心包经的原穴是( )。A.间使 B.劳宫 C.大陵 D.内关
存钱:储户A.发明:专利 B.讲课:研究员 C.诊断:病人 D.量刑:法官
关于纳税申报和缴纳税款的说法,正确的是()。A.甲公司2015年1月份成立,1
最新回复
(
0
)