Question

We tend to think of light surrounding us, like air. But light travels, always.

Bill is standing 2 meters from his mirror.
Approximately how many seconds will it take a pulse of light to bounce off his forehead, hit the mirror, and return back to his eye?

Answer 1

1.33 x 10⁻⁸ seconds

Explanation:

Assuming that the speed of light is 299,792,458 m/s, and that in order to bounce of Bill's forehead, hit the mirror and return back to his eyes, light must travel 4 meters (distance to the mirror and back) the time that it takes for light to travel is:

`t=(4)/(299,792,458) \\t=1.33*10^(-8)`

It takes 1.33 x 10⁻⁸ seconds.