JEE Main 2020PhysicsElectromagnetic WavesEasyMCQ

JEE Main 2020 — Electromagnetic Waves Question with Solution

JEE Main 2020 (02 Sep Shift 1)

Question

A plane electromagnetic wave, has frequency of 2.0×1010 Hz and its energy density is 1.02×10-8 J m-3 in vacuum. The amplitude of the magnetic field of the wave is close to 14πε0=9×109Nm2C2 and speed of light =3×108 m s-1.

Choose an option

Show full solutionCorrect option: B
Correct answer
B160 nT

Step-by-step explanation

Energy Denisty  =12B2μ0

B=2×μ0× Energy density 

B=2×4π×10-7×1.02×10-8=160×10-9=160nT

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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.