Q. A beam of natural light falls on a system of 6 polaroids, which are arranged in succession such that each polaroid is turned through $30{^\circ}$ with respct to the preceding one. The percentage of incident intensity that passes through the system will be
A) 100%
B) 50%
C) 30%
D) 12%
Explanation
(d) If $I$ is the final intensity and $I_{0}$ is the initial intensity then
$I = \frac{I_{0}}{2}\left( \cos^{2}{30{^\circ}} \right)^{5}\ or\frac{I}{I_{0}} = \frac{1}{2} \times \left( \frac{\sqrt{3}}{2} \right)^{10} = 0.12$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.