Q1 of 44 Page 20

Inian and Ezhilan argue about the light year. Inian tells that it is 9.46 × 1015 m and Ezhilan argues that it is 9.46 × 1012 km. Who is right? Justify your answer.

Speed of Light = 3 × 108 ms-1

Seconds in 1 year = 365 × 24 × 60 × 60


= 3.153 × 107 seconds


Total distance in 1 light year = speed × time


= 3 × 108 × 3.153 × 107


= 9.46 × 1015 m


1 m = 10-3 km


9.46 × 1015 m = 9.46 × 1012 km


Therefore, Inian and Ezhilan both are right.


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