Student Login

Home›Chapters›Wave Optics PYQs›Polarisation›Question 46

JEE Main 2021 (24 Feb, Shift 1) · Polarisation

Polarisation question from JEE Main 2021 (24 Feb, Shift 1)

Q46JEE Main 2021 · 24 FEB · SHIFT 1Medium

Polarisation

An unpolarised 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 ${}^\circ$ in clockwise direction, the intensity of emerging light will be _________ Lumens.

Numerical answer type. Work it out, then open the answer.

Show answer and solution

Answer: 75

Initially polarizer and analyzer are taken parallel, so the analyzer passes the full 100 lumens.
Malus's law after rotating by $30^\circ$ : $I = 100\cos^2 30^\circ = 100 \times \frac{3}{4}$
So $I = 75$ lumens.

Report a mistake

More questions on Polarisation

A polarizer - analyser set is adjusted such that the intensity of light coming out of the…JEE Main 2020 (7 Jan, Shift 1)
The Brewster's angle for the glass-air interface is (54.74)°. If a ray of light passing…MHT CET 2020 (19 Oct, Shift 2)
A beam of plane polarised light of large cross-sectional area and uniform intensity of…JEE Main 2020 (4 Sep, Shift 1)
A system of three polarizers P1, P2, P3 is set up such that the pass axis of P3 is…JEE Main 2019 (12 Apr, Shift 2)
Consider a tank made of glass(refractive index 1.5) with a thick bottom. It is filled…JEE Main 2019 (9 Jan, Shift 1)
Unpolarised light is incident from air on a plane surface of a material of refractive…NEET 2018
A plane polarized light is incident on a polariser with its pass axis making angle θ with…JEE Main 2018 (15 Apr, Shift 2)
Unpolarized light of intensity I is incident on a system of two polarizers, A followed by…JEE Main 2018 (16 Apr, Shift 1)