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
2024-04-14
24
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. [20]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. [21] 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/3555541.html
相关试题推荐
[originaltext]AmericanvisitorstoEasternAsiaareoftensurprisedandpuz
[originaltext]AmericanvisitorstoEasternAsiaareoftensurprisedandpuz
[originaltext]InBritainthebiggestnumberofworkingforeignerscomesfro
[originaltext]InBritainthebiggestnumberofworkingforeignerscomesfro
[originaltext]Thefamilyischanging.Inthepast,grandparents,parents,a
[originaltext]Thefamilyischanging.Inthepast,grandparents,parents,a
[originaltext]M:I’msotired,Ican’tseestraight.W:You’vebeentiredalot
[originaltext]W:Haveyouevervisitedaredwoodforest?Irecentlyhadachanc
[originaltext]W:Haveyouevervisitedaredwoodforest?Irecentlyhadachanc
[originaltext]M:I’mlookingforanunfurnishedtwo-bedroomapartment,butall
随机试题
TheAppalachianTrail,extendingapproximately2,020milesfromMainetoGeorgia
Itiseasiertonegotiateinitialsalaryrequirementbecauseonceyouarein
根据ISO/IEC9126软件质量模型中对软件质量特性的定义,可维护性质量特性的
《统计法》规定,统计调查中获得的( )的资料,任何单位和个人不得对外提供、泄露
下列对大承气汤主治证候的描述中哪项是错误的A.大便不通 B.频转矢气 C.腹
属于酮体的三种物质是()。A.丙酮、β-羟丁酸、乙酰乙酸 B.丙酮、丙酮
对缩宫素的叙述哪一项不正确A.小剂量适用于催产和引产 B.小剂量可加强子宫的节
A.氢氯噻嗪 B.头孢呋辛 C.头孢他啶 D.维生素K E.鱼精蛋白呋塞
某企业危化品仓库因管理不善发生火灾事故,下列关于事故发生后的应急处置措施错误的做
依据《中华人民共和国土地管理法》,经批准的非农业建设占用耕地,占用耕地单位需采取
最新回复
(
0
)