Optics Question 728
Question: A ray of light travelling inside a rectangular glass block of refractive index $ \sqrt{2} $ is incident on the glass-air surface at an angle of incidence of $ 45{}^\circ $ . The refractive index of air is 1. Under these conditions the ray
[CPMT 1972]
Options:
A) Will emerge into the air without any deviation
B) Will be reflected back into the glass
C) Will be absorbed
D) Will emerge into the air with an angle of refraction equal to 90°
Show Answer
Answer:
Correct Answer: D
Solution:
Since $ _{a}{\mu _{g}}=\sqrt{2} $ , so $ _{g}{\mu _{a}}=\frac{\sin i}{\sin r}=\frac{1}{\sqrt{2}} $
$ \therefore $ $ \sin r=1\Rightarrow r=90^{o} $
