## College Physics (4th Edition)

We can use $384,400~km$ as the distance between the Earth and the moon. We can find the time for EM waves to travel twice this distance: $t = \frac{2d}{c}$ $t = \frac{(2)(3.844\times 10^8~m)}{3.0\times 10^8~m/s}$ $t = 2.56~s$ The time delay was 2.56 seconds.