The speed of light is given by,
c=B0E0=1.5×10−82.25=1.5×108ms−1
Therefore, time taken for the echo will be,
t=c2d=1.5×1086×103=4×10−5s
A radar sends an electromagnetic signal of electric field (E_0)=2.25Vm^-1 and magnetic field (B_0)=1.5× 10^-8T which strikes a target on line of…
JEE Main 2022 — Physics Waves & Oscillations
2022mcqmedium
A radar sends an electromagnetic signal of electric field (E0)=2.25Vm−1 and magnetic field (B0)=1.5×10−8T which strikes a target on line of sight at a distance of 3km 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?
Official previous-year question
Held on 28 Jun 2022 · Verified 6 Jul 2026.
Options
- A
2.0×10−5s
- B
4.0×10−5s
- C
1.0×10−5s
- D
8.0×10−5s
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