JEE Advanced 2024 · Paper 1 · Physics Q10

← JEE Advanced 2024 · Paper 1

PhysicsInteger+4Question 27 of 51

A point source S emits unpolarized light uniformly in all directions. At two points A and B, the ratio $r = I_A/I_B$ of the intensities of light is 2. If a set of two polaroids having $45^{\circ}$ angle between their pass-axes is placed just before point B, then the new value of $r$ will be _____.

Your answer

Answer and worked solution

Official answer: 8

Unpolarized light through the first polaroid keeps $\frac12$ of its intensity; the second, at $45^\circ$ , keeps $\cos^2 45^\circ = \frac12$ of that. So $I_B' = \frac{I_B}{4}$ , and
$r' = \frac{I_A}{I_B/4} = 4 \times 2 = 8.$

Topics:Polarisation and Brewster's law

← Previous question Next question →

JEE Advanced 2024 · Paper 1, Physics question 10