Determine through what interval delta t the radio signal sent to the radio locators will return

Determine through what interval delta t the radio signal sent to the radio locators will return back being reflected from the object which is at a distance of l = 90 km.

Given:

L = 90 kilometers – distance to the object from the radar;

c = 300,000 kilometers per second – the speed of light.

It is required to determine t (seconds) – the time interval after which it will return from the radar after being reflected from the object.

The signal sent by the radar will reach the object, and then, being reflected from it, will return to the radar again. Then the total path traversed by the signal will be equal to:

S = 2 * L = 2 * 90 = 180 kilometers.

Then the signal movement time will be equal to:

t = S / c = 180/300000 = 0.0006 seconds.

Answer: The signal will return to the radar after a time interval of 0.0006 seconds.