Consider a pulse of laser light aimed at the Moon that bounces back to Earth. The distance between Earth and the Moon is 3.84 * 108 m. Show that the round-trip time for the light is 2.56 s.

Answer 1

Round trip distance is double the earth-moon distance.
Speed of light is 3*10^8 m/s.
Distance = Speed * time, so

Time = Distance /Speed
Plug in numbers and calculate time accordingly.

Answer 2

768000000