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.

Although the units of torque and work are the same,why are they not the same physical quantities?

The phenomenon of physics that deals with the constitution and structure of matter at the minute scales of atoms and nuclei is

Read each statement below carefully and state,with reasons and examples,if it is true or false:
$A$ scalar quantity is one that
$(a)$ is conserved in a process
$(b)$ can never take negative values
$(c)$ must be dimensionless
$(d)$ does not vary from one point to another in space
$(e)$ has the same value for observers with different orientations of axes.

Which of the following is the correct order of the fundamental forces in nature, arranged from weakest to strongest?

In the following list,the only pair which has different dimensions is