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
93
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、The quicker it vibrates, the greater the frequency of sound it produces.
B、The slower it vibrates, the higher the frequency of sound it produces.
C、The quicker it vibrates, the lower the frequency of sound it produces.
D、The frequency of sound it produces is not in proportion to the speed it vibrates.
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/2914888.html
相关试题推荐
[originaltext]Objectsthatarevibratingmakesounds.Rhythmicsoundvibrations
[originaltext]Inorderforachemicaltobeconsideredadrug,itmusthavethe
[originaltext]Inorderforachemicaltobeconsideredadrug,itmusthavethe
[originaltext]Inorderforachemicaltobeconsideredadrug,itmusthavethe
[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
【L1】______and【L2】______affecthowpeoplevaluepersonalcontrolindecision
WritingaLiteratureReviewI.DefinitionofLiteratureReview—It’sa(n)【T1】__
[originaltext]W:Didyourpicturesofthenightviewcomeout?M:ActuallyIra
Hemovedawayfromhisparents,andmissedthem______enjoytheexcitinglifein
OilpriccsroseinrecentdaysamongmarketfearsthatthePanamaniancrisiscou
下列关于材料一中“没收他们多余的农具与好的田地,分给他们坏的”做法评述正确的足(
下列选项中,()是汉代乐府中的著名音乐家。 A.李延年 B.李龟
万古霉素和去甲万古霉素在结构上的差别是( )。A.相差一个羟基 B.相差一个
A.清热滑痰 B.除烦止呕 C.润肠通便 D.利水退肿 E.宣肺排脓竹沥
对Ig/Igβ描述正确的是A.与mIg组成BCR复合物 B.胞质区有ITAM
最新回复
(
0
)