Question

A star is 20 light years from the Earth.
How much time does it take for the light
from the star to reach the Earth?​

Answer 1

Answer:

20 years as the statement itself says 20 light year far

Answer 2

Given:

A star is 20 light-years from the Earth.

To Find:

Time taken by the light to reach the Earth from the star

Solution:

A light-year:-

It is defined as the distance traveled by light in one year and is mainly used to express astronomical distances.

Distance between Earth and the star = 20 light-years (given)

Time taken to cover one light-year distance = 1 year

So, the time taken to cover 20 light-year distance = 20 years

Hence, the time taken by the light to reach the Earth from the star is 20 years.