JEE Main 2021PhysicsElectromagnetic WavesMediumNumerical

JEE Main 2021Electromagnetic Waves Question with Solution

JEE Main 2021 (26 Aug Shift 1)

Question

The electric field in a plane electromagnetic wave is given by
E=200cos0.5×103 m-1x-1.5×1011 rad s-1t V m-1 j^.
If this wave falls normally on a perfectly reflecting surface having an area of 100 cm2. If the radiation pressure exerted by the E.M. wave on the surface during a 10 min exposure is k109 N m-2. Find the value of k

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Show full solutionCorrect answer: 354
Correct answer
354

Step-by-step explanation

E0=200

I=12ε0E02c
Radiation pressure
P=2lc=2c12ε0E02C=ε0E02P=8.85×10-12×2002=8.85×10-8×4=354109So,k=354

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About this question

This is a previous-year question from JEE Main 2021, 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.