JEE Main 2026 Physics question
An unpolarized light of certain intensity passes through a combination of two polarizers whose transmission axes are at 30° and 90°, respectively, with respect to the horizontal axis. A third polarizer with its transmission axis at 60° with the horizontal axis is placed between the two existing polarizers. The ratio of the output intensities with and without the third polarizer is .
Answer: (C)
Solution
Without the middle polarizer: I=(I₀/2)cos²60°=I₀/8. With it: I=(I₀/2)cos²30°·cos²30°=9I₀/32. Ratio = (9I₀/32)/(I₀/8) = 9/4.