JEE Main 2026 · 4 Apr · Shift 2 · Physics Q42

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PhysicsSingle correct+4 / -1Question 42 of 75

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 ________.

3/4

4/3

9/4

4/9

Answer and worked solution

Official answer: C

Without the middle polarizer. $\frac{I_0}2\cos^260^\circ=\frac{I_0}8$ .

With it (at 60°). Each step turns by 30°: $\frac{I_0}2\cos^230^\circ\cos^230^\circ=\frac{9I_0}{32}$ .

Ratio $\frac94$ .

(C)

Topics:Polarisation and Brewster's law

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JEE Main 2026 · 4 Apr · Shift 2, Physics question 42