Light year is defined as the distance traveled by light in one year. Its value is about 9.5 x 1015 m.
Here,
Velocity of light (c) = 3 x 108 m/s
Time (t) = 1 year = 365 days = 365 x 24 x 60 x 60 sec
Distance (d) = c x t
Or, d = 3 x 108 x 365 x 24 x 60 x 60
Or, d = 9.46 x 1015 m
Or, d = 9.46 x 1012 km
Therefore, The value of light year is about 9.5 x 1015 m or 9.5 x 1012 km