Which of the following is the largest: Astronomical Unit,Light Year,or Parsec?

$10 \; amu = \dots \; kg$

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 unit of the spring constant is $J\,m^{-2}$. Is this statement true or false? If false,correct it.

Write the relation between torr and millibar.

Which of the following is not a unit of distance?