A LASER beam is a source of very intense, monochromatic and unidirectional beam.By sending a laser beam towards the moon instead of sound waves, the echo method becomes sueful in finding the distance of moon from the earth. If t is the total time taken by laser beam in going towards moon and back, then distance o moon from earth's surface is given by
s = c x t/2
Where c = 3 x 108 m/s, is the velocity of laser beam.
