Q. Two nicol prism are first crossed and then one of them is rotated through$60{^\circ}$. The percentage of incident light transmitted is
A) 1.25
B) 25.0
C) 37.5
D) 50
Explanation
(c) If $I_{0}$ is intensity of unpolarized light,
Then from 1st nicol, $I_{1} = \frac{I_{0}}{2}$
From 2nd nicol, $I_{2} = I_{1}\cos^{2}(90{^\circ} - 60{^\circ})$
$= \frac{I_{0}}{2}\left( \frac{\sqrt{3}}{2} \right)^{2} = \frac{3}{8}I_{0}$
$= \frac{I_{2}}{I_{0}} = 37.5\%$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.