Optics Question 754
Question: A ray of light is incident on the surface of separation of a medium at an angle $ 45{}^\circ $ and is refracted in the medium at an angle $ 30{}^\circ $ . What will be the velocity of light in the medium
[AFMC 1998; MH CET (Med.) 1999]
Options:
A) $ 1.96\times 10^{8} $ m/s
B) $ 2.12\times 10^{8} $ $ m/s $
C) $ 3.18\times 10^{8} $ $ m/s $
D) $ 3.33\times 18^{8} $ $ m/s $
Show Answer
Answer:
Correct Answer: B
Solution:
$ \mu =\frac{c}{v}=\frac{\sin i}{\sin r}=\frac{\sin 45^{o}}{\sin 30^{o}} $
$ \Rightarrow $ $ v=\frac{3\times 10^{8}}{\sqrt{2}}=2.12\times 10^{8} $ $ m/s $
