Q 12-10-109JEE MainJEE Main 2021 (24 Feb, Shift 1)Easy
An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by 30° in clockwise direction, the intensity of emerging light will be ______ Lumens.
Numerical value type. Enter your answer.
Answer: 75
Initially the analyzer is aligned with the polarizer and passes 100 lumens. After rotating it by $30^\circ$, Malus's law gives
$$I = 100\cos^2 30^\circ = 100\times\frac34 = 75\ \text{lumens}$$
Solution by Sreeraj P, M.Sc Physics