Question

How many nanoseconds does it take light to travel 3.50 ft in vacuum??

Answer 1

light speed in vacuum = 3.8 * 10^8

Distance (Given) = 3.5 ft

now, time = distance/speed = 3.50 / 3.8 * 10^8 = 9.21 * 10^-9 s = 9.21 nanoseconds

So, your answer is 9.21 nano-seconds...