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
34
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://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
Itisbelievedthatchildrenoftwoorthreeyearsoldareabletolearnanylan
(1)"Theworldisn’tflat,"writesEdwardGlaeser,"it’spaved."Atanyrate
建筑施工企业应依据承包工程的类型、特征、规模及自身管理水平等情况,()。A.施
下列属于信用衍生工具的是()。A.信用联结票据 B.远期外汇合约 C.货币
具有平肝息风,清热活血,补益肝肾功用的方剂是A.六味地黄丸 B.羚角钩藤汤
排尿观察异常的是A.24小时尿量2000ml B.尿呈淡黄色 C.尿液比重为
培训前对培训师的基本要求不包括()。A.在课程开始前一天,要检查教学用的活页纸
下列对投资基金销售业务描述,正确的有()。 A.未与基金管理人签订书面
集团项目组应当要求组成部分注册会计师沟通与得出集团审计结论相关的事项。沟通的内容
根据《建设工程质量管理条例》,下列不属于施工企业进行施工的依据为( )。A.施工
最新回复
(
0
)