JEE Main 2025 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 3 April 2025, Shift 1, Physics Q40

Question 40 of 75 in this shift, Physics question 15 of 25, Section A.

The radiation pressure exerted by a 450 W light source on a perfectly reflecting surface placed at 2m away from it, is

(1) $3 \times 10^{-8}$ Pascals
(2) $6 \times 10^{-8}$ PascalsOfficial answer
(3) $1.5 \times 10^{-8}$ Pascals
(4)0

Official answer

Option 2

NTA final key.

Chapter: Electromagnetic Waves
Topic: Thermal Radiation
Idea tested: Thermal Radiation Pressure

Same idea in other shifts

Asked 3× in all

8 Apr 2024, Shift 1 · Q42Average force exerted on a non-reflecting surface at normal incidence is $2.4\times10^{-4}$ N. If 360 W/cm $^2$ is the light energy flux…MediumSingle correct
28 Jul 2022, Shift 2 · Q15Sun light falls normally on a surface of area $36\ \mathrm{cm^2}$ and exerts an average force of $7.2\times10^{-9}$ N within a time period…MediumSingle correct

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.