4.5 billion km, the average separation between the sun and Neptune (report answer in hours). How long does it take light to travel each of the following distances?

t = 4.17 hours

Explanation:

given,

The distance between Sun and Neptune, d = 4.5 billion Km

= 4.5 x 10⁹ Km

= 4.5 x 10¹¹ m

The velocity of light, c = 3 x 10⁸ m/s

The velocity is always equal to displacement by the time.

V = d / t m/s

∴ t = d / V

= 4.5 x 10¹¹ m / 3 x 10⁸ m/s

= 15,000 s

= 4.17 h

Hence, the time taken by the light rays to reach the Neptune is, t = 4.17 h