Three polaroid sheets are co-axially placed such that pass axis of polaroids 2 and 3 make 30° and 90° with pass axis of sheet. If I₀ is the intensity of unpolarised light entering first sheet, the intensity of the emergent light through 3rd sheet is (a) zero (b) (3I₀)/(32) (c) 3I₀/8 (d) (3I₀)/(16)

Answer: (b). After sheet 1: I₀/2. Sheet 2 at 30°: I₀/2cos ² 30° = 3I₀/8 Sheet 3 is at 90° - 30° = 60° to sheet 2: 3I₀/8cos ² 60° = (3I₀)/(32) So the answer is (b) (3I₀)/(32).

Three polaroid sheets are co-axially placed such that pass axis of… | MHT CET 2026 (15 May, Shift 2)

Q3MHT CET 2026 · 15 MAY · SHIFT 2Medium

Polarisation

Three polaroid sheets are co-axially placed such that pass axis of polaroids $2$ and $3$ make $30^\circ$ and $90^\circ$ with pass axis of sheet. If $I_0$ is the intensity of unpolarised light entering first sheet, the intensity of the emergent light through $3^{rd}$ sheet is

Show answer and solution

Answer: (b)

After sheet 1: $I_0/2$ .
Sheet 2 at $30^\circ$ : $\frac{I_0}{2}\cos^2 30^\circ = \frac{3I_0}{8}$
Sheet 3 is at $90^\circ - 30^\circ = 60^\circ$ to sheet 2: $\frac{3I_0}{8}\cos^2 60^\circ = \frac{3I_0}{32}$
So the answer is (b) $\frac{3I_0}{32}$ .

Report a mistake

Polarisation question from MHT CET 2026 (15 May, Shift 2)

More questions on Polarisation