Question

If the distance between the sun and earth is 1.5*10^11m and velocity of light is 3*10^8m/s.Time taken by light to reach the earth from sun is

Answer 1

given
distance = 1.5 x 10^11 m
light travels in straight line so it becomes displacement = 1.5 x 10^11 m
velocity = 3 x 10^8 m/s
we know that
velocity = displacement/ time
time = displacement/velocity
        = 1.5 x 10^11/ 3 x 10^8
         =0.5 x 10^3 = 0.5 x 1000 = 500s
therefore time taken for sunlight to reach earth is just 500s(nearly 8hrs)