Question

It takes 5 years for light to reach the earth frm star express distance of star from earth in 1 light year 2 in km​

Answer 1

Hey there!

i) The distance travelled by the light in 1 year is called 1 light year.

Thus the distance travelled by light in 5 years = 5 light years.

ii) 1 light year = Speed of light * time in 1 year

                     = (3 * 10^8) * (3.153 * 10^7) = 9.46 * 10^15 m = 9.46 * 10^12 km

Distance of a star from the earth = 5 * 9.46 * 10^12 km = 4.73 * 10^13 km

Hope It Helps You!