3 - University Physics with Modern Physics

Question

How many nanoseconds does it take light to travel 1.00 ft in vacuum? (This result is a useful quantity to remember.)?

 

Step-by-Step Solution

Answer

Light takes 1.016 nanoseconds to travel 1 ft distance in vacuum.

Speed of light in vacuum

When light travels through the vacuum, it has the maximum speed. The speed of light in a vacuum is 3x10⁸ m/s. No object in the universe can travel more than this speed.

 Given data:

The distance traveled in vacuum is d = 1 ft.

The speed of light in vacuum is v=3x10⁸ m/s.

 

Calculation of time in nanoseconds

Since, formula of speed of light is the ratio of distance travelled by the light to the time taken to travel that distance. 

 $$\begin{gathered} v=\frac{d}{t} \\ 3\times {10}^{8}m/s=\frac{1 ft\times {\displaystyle \frac{0.3048 m}{1 ft}}}{t} \\ t=1.016\times {10}^{-9}s \times \frac{1 ns}{1\times {10}^{-9}s} \\ t=1.016 ns \end{gathered}$$

Hence from the above calculation, it seems light takes 1.016 nanoseconds to travel 1 ft distance in vacuum.