首页
登录
职称英语
[originaltext]Objects that are vibrating make sounds. Rhythmic sound vibrations
[originaltext]Objects that are vibrating make sounds. Rhythmic sound vibrations
游客
2023-08-10
99
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. [23] 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. [24] 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. [25-1] Using sound to find or “see” things is called echolocation. Another animal that uses ultrasound is the dolphin. Dolphin scan hear sounds up to about 150,000 hertz. Dolphins use sound waves to find food underwater. [25-2] 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. [25-3] Dolphins’ ultrasound ability is so sensitive that they can detect small fish from 10 feet away.
23.What is the relationship between the vibration of an object and the frequency of its sound?
24.What sounds can humans hear?
25.According to the speaker, what is the phenomenon of echolocation?
选项
A、Those with frequencies lower than 20 hertz.
B、Those with frequencies about 21,000 hertz.
C、Those with frequencies from 20 hertz to 20,000 hertz.
D、Those with frequencies higher than 20,000 hertz.
答案
C
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2914889.html
相关试题推荐
[originaltext]Objectsthatarevibratingmakesounds.Rhythmicsoundvibrations
[originaltext]Inorderforachemicaltobeconsideredadrug,itmusthavethe
[originaltext]Inorderforachemicaltobeconsideredadrug,itmusthavethe
[originaltext]Hi,everybody.AsIsaidinmyStateoftheUnionaddress,weliv
[originaltext]Hi,everybody.AsIsaidinmyStateoftheUnionaddress,weliv
[originaltext]IntheUnitedStates,manypeopleoncelivedinlarge,two-and-th
[originaltext]Easterisamixofthreetraditions:Pagan,HebrewandChristian.
[originaltext]Easterisamixofthreetraditions:Pagan,HebrewandChristian.
[originaltext]W:2millionhighschoolseniorsaregearingupthisfalltoappl
[originaltext]W:2millionhighschoolseniorsaregearingupthisfalltoappl
随机试题
[originaltext]Bridgeshavebeenaroundforanawfullylongtime.Theoldest
[originaltext]Afewdegreescanmakeabigdifferencewhenitcomestofood
KatharineGrahamgraduatedfromtheUniversityofChicagoin1938andgota
统计可以应用于所有领域,几乎毫无例外。( )
(2018年真题)通过各种通信方式,不通过集中的交易所,实行分散的、一对一交易的
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性: A.如
教育行政部门取缔了一批违反国家规定私自招收未成年学生的私立学校,教育行政部门这一
在代理制度中,由他人以自己的名义代为民事法律行为,并承受法律后果的人,称()。A
“当日无负债”指的是当客户当天交易发生亏损导致保证金账户资金不足时,则要求其必须
压入式通风方式可采用胶质或塑料等柔性风筒,其优点是()。A.排除炮烟所需
最新回复
(
0
)