Question 157: Ray Optics

Question

A ray of light AO in vacuum is incident on a
glass slab at angle 60° and refracted at angle 30°
along OB as shown in the figure. The optical path
length of light ray from A to B is:
![](https://imagex.cdn.examgoal.net/3rsa0w2w9jwyutqof/1c8b8632-6670-4fb9-900b-c0b0f0dde0be/29d46df0-9028-11e9-86c1-73f7f991b766/file-3rsa0w2w9jwyutqog.png)

Accepted Answer

From SnellÃ¢ÂÂs law
1 sin 60ÃÂ° = $\mu $ sin 30ÃÂ°
$ \Rightarrow $ $\mu $ = $\sqrt 3 $
Optical path = AO + $\mu $(OB)
= ${a \over {\cos {{60}^o}}} + \sqrt 3 {b \over {\cos {{30}^o}}}$
= 2a + 2b

Answer

2a + 2b/$\sqrt 3$

Answer

2a + 2b/3

Answer

2a + 2b

Answer

2$\sqrt3$/a + 2b

Ray Optics

A ray of light AO in vacuum is incident on a glass slab at angle 60° and refracted at angle 30° along OB as shown in the figure. The optical path length of light ray from A to B is:

Choose the correct answer: