The given statement is true because a dimensionless quantity may be large or small in comparison to some standard reference. For example, the coefficient of friction is dimensionless. The coefficient of sliding friction is greater than the coefficient of rolling friction, but less than static friction.
a) An atom is a very small object in comparison to a soccer ball.
b) A jet plane moves with a speed greater than that of a bicycle.
c) Mass of Jupiter is very large as compared to the mass of a cricket ball.
d) The air inside this room contains a large number of molecules as compared to that present in a geometry box.
e) A proton is more massive than an electron.
f) Speed of sound is less than the speed of light.
The quantity used as a standard of measurement is called unit.
Example: Unit of time is second.
Define physical quantity.