首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、The quicker it vibrates, the greater the frequency of sound it produces. B、The slower it vibrates, the higher the frequency of
A、The quicker it vibrates, the greater the frequency of sound it produces. B、The slower it vibrates, the higher the frequency of
admin
2016-11-26
17
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.
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、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
短文提到,物体振动得越快,它制造的声音频率就越高。A为录音原文中the more…the greater结构的同义表达,故为正确答案。B与C意思相同,可同时排除;D明显与原文内容相冲突。
转载请注明原文地址:https://kaotiyun.com/show/YGF7777K
0
大学英语六级
相关试题推荐
Manycountriesneedtodomoretooffereducationandtrainingforpeopleofallages.SosaysanewreportfromtheOrganizatio
WhenwestartedtheMeyerhoffScholarsProgramnearly20yearsago,wefacedamajorchallenge—helpingstudentsofcolorachieve
TheStoneAge,theIronAge.Entireepochshavebeennamedformaterials.Sowhattocallthedecadesahead?Thechoicewillbe
TheStoneAge,theIronAge.Entireepochshavebeennamedformaterials.Sowhattocallthedecadesahead?Thechoicewillbe
GeorgeWilliams,oneofScottsdale’slastremainingcowboys,hasbeenraisinghorsesandcattleonhis120acresfor20years.T
A、Someoneshouldbeputinchargeofofficesupplies.B、Themancanleavethediscsintheofficecabinet.C、Themanmayfindth
A、Tolookitupinhertextbook.B、TosearchontheInternet.C、Toaskherprofessorforhelp.D、Togotothelibrary.B
It’sTimetoPayAttentiontoSleep,theNewHealthFrontier[A]Yourdoctorcouldsoonbeprescribingcrucialsleepastreatment
Forauthorsofself-helpguides,nohumanproblemistoogreatortoosmall.Wanttobecomefitter,richerorhappierin2015?T
Electroniccigarettesarehandheldnicotine-deliverydevicesthat,despiteadevotedfollowing,arecurrentlyswirlingincontro
随机试题
底物对酶合成的影响是
环境温度低于24℃、湿度低于70%时,使用纺织品材料包装的无菌物品的有效期宜为
深静脉血栓形成的患者,抗凝治疗期间最严重的并发症是
城市控制性详细规划,是以城市总体规划或分区规划为依据,确定()。
信贷业务是商业银行传统的主要业务,()是商业银行利润的主要来源。
班级活动的选题是班级活动的中心环节,是活动全过程的关键。()
公安机关要建立(),通过治安信息的收集与分析,不断提高对治安危害的预见性,加强超前控制。
下列情况下,按照属地管辖原则适用《中华人民共和困刑法》的是:
[2007年MBA真题]神经化学物质的失衡可以引起人的行为失常,大到严重的精神疾病,小到常见的孤僻、抑郁甚至暴躁、嫉妒。神经化学的这些发现,使我们不但对精神疾病患者,而且对身边原本生厌的怪癖行为者,怀有同情和容忍。因为精神健康,无非是指具有平衡的神经化学物
Writealettertoamuseum’sstafftoaskforsomeinformationaboutahistoricalexhibition.Youshouldincludethedetailsyo
最新回复
(
0
)