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
2024-03-10
6
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. 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、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。录音提到,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://www.tihaiku.com/zcyy/3521991.html
相关试题推荐
[originaltext]InAmerica,driver’seducationispartoftheregularhighsc
[originaltext]InAmerica,driver’seducationispartoftheregularhighsc
[originaltext]Yuppiesareyoungpeoplewhoearnalotofmoneyandlivein
[originaltext]Yuppiesareyoungpeoplewhoearnalotofmoneyandlivein
[originaltext]DuringtheChristmasshoppingrushinLondon,aninteresting
[originaltext]DuringtheChristmasshoppingrushinLondon,aninteresting
[originaltext]DuringtheChristmasshoppingrushinLondon,aninteresting
[originaltext]DuringtheChristmasshoppingrushinLondon,aninteresting
[originaltext]Objectsthatarevibratingmakesounds.Rhythmicsoundvibrat
[originaltext]Objectsthatarevibratingmakesounds.Rhythmicsoundvibrat
随机试题
Whatwastheresultofthetests?Theresultwasthathefoundthemonkeytobe
关于商标的内涵,下列说法不正确的是( )。A.商标应当具有显著特征 B.商标
严重新生儿高胆红素血症,患儿经蓝紫光照射治疗无效或出现溶血时需进行的治疗是(
肺癌中发病率最高的是()A.腺癌 B.鳞癌 C.细支气管肺泡癌 D.
饭店为住店客人提供的贵重物品保管服务应当( )。A.按照规定的时限并免费提供
患者感冒后出现发热、恶风、头痛、汗出,治宜A.麻黄汤 B.桂枝汤 C.葛根汤
关于头孢曲松的叙述,错误的是()A.对革兰阴性菌有较强抗菌作用 B.对
(2021年真题)下列各项中,关于现金股利的会计处理正确的有()。A.计提
根据《工作保险条例》,职工因工致残,应当保留劳动关系,退出工作岗位的伤残等级范围
"冬眠合剂"通常指下述哪一组药物?A.氯丙嗪+阿托品+哌替啶 B.苯巴比妥+氯
最新回复
(
0
)