Question

The distance of a galaxy from the earth is 5.6×10^25. Assuming the speed of light to be 3×10^8 m per s.Find the time taken by light to travel this distance.

Answer 1

Distance=5.6×10^25m (you haven't mentioned the unit so i am assuming it to be meters)

Speed=3×10^8 m/s

Using speed=distance/time

Therefore,

Time= speed/distance

= 5.6×10^25/3×10^8

= 1.8667×10^17 s