Question

A RADAR sends a signal to an aeroplane at a distance 300 km away, with a speed of 3 × 10^8 m s^{-1}. After how much time is the signal received back after reflecting from the aeroplane?​

Answer 1

Explanation:

Given that,

●Speed of sound transmitted from RADAR = $\sf{3 × 10^{8} m s^{-1}}$

●The distance at which the signal is transmitted = 300 km = $\sf{3 × 10^5 m}$

↪The signal travels twice, i.e when transmitted and when it is being received by the RADAR, the distance is calculated twice.

↪Total distance the signal travels = $\sf{2 × 3 × 10^5m}$

Time taken to receive the signal back after reflecting from the aeroplane is

$\green \bigstar \boxed{ \sf \: Time = \frac{Distance}{Speed} }\\ \\ \sf [ Putting \: values ] \\ \\ </h3><h3> \leadsto \sf \: t = \frac{(2 × 3 × 10 {}^{5} )}{ 3 × 10^{8} }\\ \\ </h3><p></p><h3> \: \: \: \: \: \: \: \: \: \: \: \: \: \: \leadsto \sf \: t = 0.002 seconds \: \: \red\bigstar$

Therefore after 0.002 seconds, the signal is received back after reflecting from the aeroplane.