Question

On 20 July 1969, the astronauts of Apollo 11 placed a reflector on the surface

of the moon that with the telescope and electronic equipment on earth allows

measurements of the time of flight of laser pulses from earth to the moon and

back. Scientists are able to measure the time of flight of laser pulse from earth

to the moon and back with an accuracy of one nanosecond. What is the

accuracy of the distance to the moon distance?

Answer 1

$\Delta l=\frac{c\Delta t}2=15~cm.$