physic light
2008-12-21 9:33 pm
A light ray is incident on a glass window at an angle of 30 to the normal. At what angle (to the normal) does it go out from the other side ?
(Given : refractive index of glass = 1.5)
A. 19.5
B. 30
C. 48.6
D. 60
p.s. don't just give me the ans ...plz explain...thz
the ans should be B.
回答 (2)
2008-12-21 9:59 pm
✔ 最佳答案
Using 司乃耳定律(Snell's law)n1sinθ1=n2sinθ2
1*sin30=1.5sinθ2
sinθ2=1/3
θ2=19.5
The answer is A
2008-12-21 14:00:05 補充：
media 1 : air media 2 : glass
2008-12-21 18:58:25 補充：
OK。我認錯。因為看得太快(the ans should be B)我都沒有看到。
條路徑係空條->玻璃->空氣。當第二階段時
n1sinθ1=n2sinθ2
1.5*sin19.5=1sinθ2
sinθ2=1/2
θ2=30
The answer is B
2008-12-21 10:02 pm
To myisland8132, 題目說了go out from the other side. 即光由空氣進入玻璃，再由玻璃出去空氣。簡單來說，即前後的medium沒有變，皆為空氣。所以angle of refraction也是30*.
收錄日期: 2021-04-26 13:14:36
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081221000051KK00749