首页
登录
职称英语
[originaltext] If you’re driving on a highway, the only thing keeping you fr
[originaltext] If you’re driving on a highway, the only thing keeping you fr
游客
2023-08-30
11
管理
问题
If you’re driving on a highway, the only thing keeping you from going faster than the speed limit is your sense of civic duty, or perhaps that police car up ahead. There’s one speed limit, however, that most scientists agree nothing will ever break. That’s the speed of light: 186, 280 miles per second. As it trav-els through deep space, light moves at exactly this speed, no more and no less. The speed of light is so reliable, we even use it to measure distances between the stars. If it takes starlight fifty years to reach us, we say that this star is fifty light years away. You might be surprised to learn, however, that light itself does not always travel at the speed of light. Our highways generally have a higher speed limit, but once you enter a city or residential street, the speed limit lowers. Likewise, light travels at its maximum speed through a vacuum but it slows down when it enters air, water, or some other medium. Through air, light moves a little slower: forty miles per second less than its maximum speed. Through glass, light moves almost eighty thousand miles per second slower.Light moves more than a hundred thousand miles per second slower through a diamond less than half its speed in a vacuum. Light moves so quickly anyway, do we ever notice this change in speed? Actually, we do. When light slows down it also bends slightly. If light always moved at its maximum speed, none of our telescopes, eyeglasses or even our eyes themselves would ever work.
1.What does the passage mainly talk about?
2.Why do we use light speed to measure distances between the stars?
3.What will happen if light moves through a diamond?
4.What would happen if light always moved at its maximum speed?
选项
A、Because the speed of light changes easily.
B、Because light slows down when it enters other medium.
C、Because light moves very fast.
D、Because the speed of light is reliable.
答案
D
解析
转载请注明原文地址:https://www.tihaiku.com/zcyy/2970173.html
相关试题推荐
[originaltext]M:Lisa,doyouthinkwemaketoomuchuseoftinnedandfrozenfo
[originaltext]M:Lisa,doyouthinkwemaketoomuchuseoftinnedandfrozenfo
[originaltext]M:Lisa,doyouthinkwemaketoomuchuseoftinnedandfrozenfo
[originaltext]M:Hello.InternationalFriendsClub.CanIhelpyou?W:Oh,hell
[originaltext]M:Hello.InternationalFriendsClub.CanIhelpyou?W:Oh,hell
[originaltext]M:Hello.InternationalFriendsClub.CanIhelpyou?W:Oh,hell
[originaltext]M:Haveyoucheckedallthedoorsandwindows?Andhaveyoubroug
[originaltext]M:Haveyoucheckedallthedoorsandwindows?Andhaveyoubroug
[originaltext]M:Haveyoucheckedallthedoorsandwindows?Andhaveyoubroug
[originaltext]M:Haveyoucheckedallthedoorsandwindows?Andhaveyoubroug
随机试题
Whatisthispassagemainlyabout?[br][originaltext]Therearemanyreason
Scientistshavecomeupwithatheoryforwhytimeflieswhenyonarehaving
核酶的底物是A.RNA B.核蛋白 C.DNA D.核糖体
全口义齿初戴时发现下牙弓明显后退其原因最可能是A.牙合架前后移动 B.确定水平
下列不为五倍子功效的是A、敛肺降火 B、涩肠止泻 C、宁心安神 D、固精止
下列有关新陈代谢的表述不正确的是: A.光合作用属于绿色植物新陈代谢的
基金管理公司监察稽核部的主要工作包括()。 A.基金管理稽核B.财务
心理咨询时通过与个体持续的、直接的接触,向其提供心理帮助并力图促使其行为、态度发
A.水丸 B.糖丸 C.糊丸 D.滴丸 E.蜡丸疗效迅速,生物利用度高的
根据《建筑法》,关于建筑安全生产管理的说法,正确的是()。A.要求企业为从
最新回复
(
0
)