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
2023-08-05
18
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. [9] 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. [10] 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. [11] 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. [11] 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.
9. What is the relationship between the vibration of an object and the frequency of its sound?
10. What sounds can humans hear?
11. 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 lower than 20,000 hertz.
D、Those with frequencies higher than 20,000 hertz.
答案
C
解析
录音提到,人类可以听见频率在20赫兹到2万赫兹之间的声音。由此可知,C为正确答案。
转载请注明原文地址:https://tihaiku.com/zcyy/2900073.html
相关试题推荐
[originaltext](23)WiththeInternetrevolutionusheringinnewmodesofco
[originaltext]Hereisaquestionforyou.Thecustomerisalwaysright.Rig
[originaltext]Hereisaquestionforyou.Thecustomerisalwaysright.Rig
[originaltext]Moderator:Hello,ladiesandgentlemen.Itgivesmegreat
[originaltext]Moderator:Hello,ladiesandgentlemen.Itgivesmegreat
[originaltext]TheWorldHealthOrganizationsays57nationsinSouthernAfr
[originaltext]TheWorldHealthOrganizationsays57nationsinSouthernAfr
[originaltext]TheWorldHealthOrganizationsays57nationsinSouthernAfr
[originaltext]W:WhatdoyouthinkofTV?Ithinkitisafalsegod,adang
[originaltext]W:WhatdoyouthinkofTV?Ithinkitisafalsegod,adang
随机试题
Rodwasalreadyanestablishedlabheadwhenhedecidedheneededtolearnm
ManytheoristsnowdoubtthatheatlossfromEarth’scoreandradioactivedecay
Didyouknowthatinfantsprefertheirmothers’voicestothatofotherfema
嗜碱性点彩细胞计数的染色方法为A.血膜片甲醛固定后染色法 B.活体染色法 C
甲、乙、丙经营普通合伙企业,约定由甲代表合伙企业执行合伙企业事务,后来乙擅自代表
机体代谢过程中产生最多的酸性物质是()。A.碳酸 B.硫酸 C.乳酸 D
推荐用终点法进行检测的是A.ALTB.ASTC.ALPD.AMYE.TG
()是指受托经纪人只将基本房源信息推荐给其他经纪人,其他经纪人若有合适的客户
你工作中出了一点差错,一个平时爱打小报告的同事,跑到上司那里告了你一状,你觉得上
(2019年真题)下列税种中,由海关系统负责征收和管理的是()。A.契税 B
最新回复
(
0
)