How long will a radio wave, with a wave length of 200 m takes to travel to and for the moon from the earth? (Distance of moon from earth = 3.9 x 108 m)

Answer 1

speed of electromagnetic wave is about 3*10^8 m/s
distance = 2 *3.9*10^8 m

time = distance/speed
= 7.8*10^8/3*10^8
=7.8/3 seconds