The distance of a galaxy is of the order of $10^{25} \ m$. Calculate the order of magnitude of time taken by light to reach us from the galaxy.

$Joule-second$ is the unit of

Identify the incorrect statement among the following.

$0.1 \, Pa = \dots \, Nm^{-2} = \dots \, \text{dyne} \, cm^{-2}$.

If the gravitational force,electromagnetic force,strong nuclear force,and weak nuclear force are represented by $GF, EMF, SNF$,and $WNF$ respectively,then which of the following represents the correct order of their relative strengths?

Which of the following is different from the others in terms of units?