Learn

Friday, 9 October

JEE Main Physics · Electromagnetic Waves

Thermal Radiation in JEE Main

Thermal Radiation (Physics, Electromagnetic Waves) came 3 times in 3 of the 42 JEE Main shifts Lumi analysed, across 2 distinct ideas. 3 of them came in 2024–26; it was last asked in 2025.

Questions
3
in 3 shifts
Ideas asked
2
1 asked more than once
Numerical answer
1
33% of its questions
Pattern
New since 2024
last asked 2025
Questions each year
0240’170’200’210’220’231’242’250’26

In the shifts Lumi analysed for each year.

Difficulty and format
Easy 0Medium 3Hard 0

Format

  • Single correct2 Q
  • Numerical value1 Q
Ideas inside the topic
2 ideas
Where it sits

Part of Electromagnetic Waves, which had 36 questions in all. Thermal Radiation accounts for 8% of them. In Lumi's JEE taxonomy it belongs to Thermodynamics.

Some questions sit in other chapters too: Thermal Properties of Matter.

Every question

All 3 Thermal Radiation questions

Newest first, each with its options and official answer.

  1. 3 Apr 2025, Shift 1 · Q40The radiation pressure exerted by a 450 W light source on a perfectly reflecting surface placed at 2m away from it, isMediumSingle correct
  2. 7 Apr 2025, Shift 1 · Q47A wire of length 10 cm and diameter 0.5 mm is used in a bulb. The temperature of the wire is 1727∘1727^\circC and power radiated by the wire…MediumNumerical value
  3. 8 Apr 2024, Shift 1 · Q42Average force exerted on a non-reflecting surface at normal incidence is 2.4×10−42.4\times10^{-4} N. If 360 W/cm2^2 is the light energy flux…MediumSingle correct