Optics Question 972
Question: With respect to air critical angle in a medium for light of red colour $ [{\lambda _{1}}] $ is q. Other facts remaining same, critical angle for light of yellow colour $ [{\lambda _{2}} $ ] will be [MP PET 1999]
Options:
A) $ \theta $
B) More than $ \theta $
C) Less than $ \theta $
D) $ \frac{\theta {\lambda _{1}}}{{\lambda _{2}}} $
Show Answer
Answer:
Correct Answer: C
Solution:
Critical angle = $ {{\sin }^{-1}}( \frac{1}{\mu } ) $ \ $ \theta ={{\sin }^{-1}}( \frac{1}{{\mu _{{\lambda _{1}}}}} ) $ and $ \theta ‘={{\sin }^{-1}}( \frac{1}{{\mu _{{\lambda _{2}}}}} ) $
Since $ {\mu _{{\lambda _{2}}}}>{\mu _{{\lambda _{1}}}} $ , hence $ \theta ‘<\theta $
