Question

A new unit of length is chosen such that the speed of light in vaccum is unity. What is the distance between the sun and the earth in terms of the new unit if light takes 8min and 20 s to cover this distance.

Answer 1

Speed of light in a vacuum is unity,

Speed of light = 1 unit

Time taken = t = 8 min 20 s

8 × 60 + 20 = 480 + 20 = 500 s

To Find,

Distance between the Sun and the Earth,

Here, we know that,

Distance between the Sun and the Earth = Speed of light × Time taken by light to cover the distance.

So, putting all the values, we get

= Distance between the Sun and the Earth = 1 × 500

= Distance between the Sun and the Earth = 500 units

Hence, Distance between the Sun and the Earth is 500 units.