A laser light beamed at the moon the takes `2.56 s` to return after reflection at the moon's surface . How much is the radius of the lunar orbit around the earth ?

Explanation

`t=2.56s`
`therefore` t = time taken by laser beam to go to the moon = `(t)/(2)`
distance between earth and moon
`=d=cxx(t)/(2)`
`=3xx10^(8)xx(2.56)/(2)`
`=3.84xx10^(8)m`.