JEE Main 2022PhysicsWaves and SoundMediumMCQ

JEE Main 2022 — Waves and Sound Question with Solution

JEE Main 2022 (28 Jun Shift 1)

Question

A radar sends an electromagnetic signal of electric field E0=2.25 V m-1 and magnetic field B0=1.5×10-8 T which strikes a target on line of sight at a distance of 3 km in a medium. After that, a part of signal (echo) reflects back towards the radar with same velocity and by same path. If the signal was transmitted at time t=0 from radar, then after how much time echo will reach to the radar?

Choose an option

Show full solutionCorrect option: B
Correct answer
B4.0×10-5 s

Step-by-step explanation

The speed of light is given by,

c=E0 B0=2.251.5×10-8=1.5×108 m s-1

Therefore, time taken for the echo will be,

t=2dc=6×1031.5×108=4×10-5 s

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About this question

This is a previous-year question from JEE Main 2022, covering the Waves and Sound 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.