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Saturday, 31 October

JEE Main 2022 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 28 June 2022, Shift 1, Physics Q41

Question 41 of 90 in this shift, Physics question 11 of 30, Section A.

A radar sends an electromagnetic signal of electric field (Eo\mathrm{E_o}) = 2.25 V/m and magnetic field (Bo\mathrm{B_o}) = 1.5×10−81.5\times10^{-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?
  1. (1)2.0×10−52.0\times10^{-5} s
  2. (2)4.0×10−54.0\times10^{-5} sOfficial answer
  3. (3)1.0×10−51.0\times10^{-5} s
  4. (4)8.0×10−58.0\times10^{-5} s

Official answer

Option 2

NTA final key.

Chapter
Electromagnetic Waves
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.