JEE Main 2020PhysicsElectromagnetic WavesDisplacement Current And Properties Of Em WavesmediumMCQ

JEE Main 2020Electromagnetic Waves Question with Solution

From: JEE Main 2020 (Online) 2nd September Morning Slot

Question

A plane electromagnetic wave, has
frequency of 2.0 1010 Hz and its energy density is 1.02 10–8 J/m3 in vacuum. The amplitude of the magnetic field of the wave is close to
( and speed of light
= 3 108 ms–1)

Choose an option

Show full solutionCorrect option: C
Correct answer
C160 nT

Step-by-step explanation

Energy density,

1.02 10–8 =

Also, c =



= 1.02 10–8 2

= 1.02 10–8 2

B0 = 16 10-8 T = 160 nT

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Electromagnetic Waves chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2020, covering the Electromagnetic Waves chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.