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
36
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
Thisis______astheoneyouboughttheotherday.A、suchgoodapictureB、soag
为了实现这个目标,国家决定重点发展农村地区与预防医学。Torealizethetargets,theStatehasoptedtopriori
WhenSakenaYacoobiwasachildinHerat,Afghanistan,shesawmanywomensu
A. B. C. D.无法判断
试回答交通标志产品各项试验检测频率及结果判定规则的相关问题。(3)检测结果为(1
统计某月份商品平均价格的计算方法如图8所示。将E2单元格的公式移动到E
下列抗癫痫药物中属于肝药酶抑制剂的是A.苯巴比妥 B.丙戊酸钠 C.苯妥英钠
2,2,2,,,( )
区域环境承载力最终表征为区域所能承受的社会经济规模和()。A.生物资源
天元公司和地方公司签订建设工程施工合同,约定由地方公司承建天元公司位于A市的写字
最新回复
(
0
)