Among the following, the least unit for length is:

Give the unit of the torsional constant.

Explain this statement clearly: "To call a dimensional quantity 'large' or 'small' is meaningless without specifying a standard for comparison". In view of this,reframe the following statements wherever necessary:
$(a)$ atoms are very small objects
$(b)$ a jet plane moves with great speed
$(c)$ the mass of Jupiter is very large
$(d)$ the air inside this room contains a large number of molecules
$(e)$ a proton is much more massive than an electron
$(f)$ the speed of sound is much smaller than the speed of light.

The $SI$ unit of pressure is:

What is $1\,AU$? It represents which physical quantity?

If $1 \ gm \ cm \ s^{-1} = x \ Ns$,then $x = $