Question

Which of the following is not a unit of time?

Answer 1

Correct option is D. light year
Here, hour, nano second and microsecond are all the unit of time.

1 hour $$=3600$$ second, one nano second $$=10^{9}$$ second, one microsecond $$=10^{-6}$$ second

Light year is the unit of astronomical distance and it is equivalent to distance traveled by light in one year.