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
2024-05-06
48
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、Driving a car on a highway.
B、The speed limit.
C、The speed of light.
D、The way our eyes see light.
答案
C
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3586436.html
相关试题推荐
[originaltext]Ifyou’redrivingonahighway,theonlythingkeepingyoufr
[originaltext]Ifyou’redrivingonahighway,theonlythingkeepingyoufr
[originaltext]Ifyou’redrivingonahighway,theonlythingkeepingyoufr
[originaltext]Ifyou’redrivingonahighway,theonlythingkeepingyoufr
[originaltext]EmilyDickinsonisoneofthegreatestAmericanpoets.Shewa
[originaltext]EmilyDickinsonisoneofthegreatestAmericanpoets.Shewa
[originaltext]M:Bob’swritingtoinvitemetospendaweekendwithhimathis
[originaltext]M:Bob’swritingtoinvitemetospendaweekendwithhimathis
[originaltext]M:Right,Iguessyou’vegotsomeideasforourproductpromotion
[originaltext]M:Right,Iguessyou’vegotsomeideasforourproductpromotion
随机试题
It’s10p.m.Youmaynotknowwhereyourchildis.Butthechipdoes.T
—Letmeaskyousomequestionsabouttheaccidentyouwitnessed.—______—Thank
YYZZZYZZYisto221112112asYYZZYZZYisto______.2.21121e+007(从题意可知,Y相当于2,Z相当于1
轴力背离截面为负;轴力指向截面为正。
A.血磷升高 B.血钙降低 C.两者都有 D.两者都无维生素D代谢障碍时
仲裁又称为( )。A.协商 B.诉讼 C.公断 D.打官司
A.异丙肾上腺素 B.克伦特罗 C.色甘酸钠 D.二丙酸倍氯米松 E.沙
双胍类降血糖作用的机制是A.刺激胰岛B细胞 B.抑制糖原异生,促进组织摄取葡萄
2008年7月1日,昆明特大暴雨造成库存的刺五加注射液被雨水浸泡。某药业公司云南
某施工单位在土方施工作业过程中,为有效防治扬尘大气污染,施工现场采取比较得当的措
最新回复
(
0
)