A physics teacher asked a student to find how much time does the light take to reach the earth if the distance between the sun and the earth is `150xx10^(6)km`? Teacher also gives an extra input that velocity of light is `3xx10^(8)ms^(-1)`. What would be the answer of the student?

Explanation

Velocity of light, `c= 3 xx 10^8 m s^(-1)`.
Distance of the sun from the earth,
`d = 150 xx 10^6 km `.
` = 150 xx 10^6 xx 10^3`
` = 150 xx 10^9 m`
Velocity ` = d/r`
` t = (150 xx 10^9m)/(3 xx 10^8 ms^(-1)) = 500s`
= 8.33 minute
` therefore ` light takes 8.33 minute to reach the surface of the earth from the sun.