Q. The figure shows four pairs of polarizing sheets, seen face-on. Each pair is mounted in the path of initially unpolarised light. The polarizing direction of each sheet (indicated by the dashed line) is referenced to either a horizontal $x$-axis or a vertical $y$ axis. Rank the pair according to the fraction of the initial intensity that they pass, greatest first
A) (i) > (ii) > (iii) > (iv)
B) (i) > (iv) > (ii) > (iii)
C) (i) > (iii) > (ii) > (iv)
D) (iv) > (iii) > (ii) > (i)
Explanation
(b) Final intensity of light is given by Malus law $I = I_{0}\cos^{2}\theta$; where $\theta =$ Angle between transmission axes of polarizer and analyser
Hence decreasing order of intensity is (i) > (iv) > (ii) > (iii)
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.