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A radar sends an electromagnetic signal of electric field ( E 0 ) = 2.25 V/m and magnetic field ( B 0) = 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?

1. 2.0 × 10 –5 s
2. 4.0 × 10 –5 s
3. 1.0 × 10 –5 s
4. 8.0 × 10 –5 s

Correct answer: 4.0 × 10 –5 s

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