A new unit of length is so chosen that the speed of light in vacuum is unity. What is the distance (in this new unit) between the sun and the earth if light takes 8 min and 20 second to reach the earth from the sun?

Options

A. 300
B. 400
C. 500
D. 600

Answer

C

Explanation

c = speed of light = 1 new unit of length `s^(-1)`
8min 20s `= 8 xx 60+ 20 = 500` s
Distance between sun and the earth
= ct = 1 new unit of length `s^(-1) xx500` s
= 500 new unit of length