A beam of plane polarised light of large cross-sectional area and uniform intensity of 3.3 Wm$^{-2}$ falls normally on a polariser (cross sectional area $3\times10^{-4}$ m$^2$) which rotates about its axis with an angular speed of 31.4 rad/s. The energy of light passing through the polariser per revolution, is close to :

JEE Main 2020 · PhysicsMultiple choiceSingle correctHardMulti-step

JEE Main 4 September 2020, Shift 1, Physics Q17

Question 17 of 75 in this shift, Physics question 17 of 25.

A beam of plane polarised light of large cross-sectional area and uniform intensity of 3.3 Wm

^{-2}

falls normally on a polariser (cross sectional area

3\times10^{-4}

^2

) which rotates about its axis with an angular speed of 31.4 rad/s. The energy of light passing through the polariser per revolution, is close to :

(1) $1.0\times10^{-5}$ J
(2) $1.0\times10^{-4}$ JOfficial answer
(3) $1.5\times10^{-4}$ J
(4) $5.0\times10^{-4}$ J

Official answer

Option 2

NTA final key (Sep 2020).

Chapter: Wave Optics
Topic: Polarization
Idea tested: Time-Averaged Intensity in Rotating Analyzer

Same topic in other shifts

All Polarization questions

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.