How do you classify the physical quantities on the basis of dimension ?

Explanation

(1) Dimensional variables: Physical quantities, which possess dimensions and have variable values are called dimensional variables. Examples are length, velocity, and acceleration etc.
(2) Dimensionless variables: Physical quantities which have no dimensions, but have variable values are called dimensionless variables. Examples are specific gravity, strain, refractive index etc.
(3) Dimensional Constant: Physical quantities which possess dimensions and have constant values are called dimensional constants. Examples are Gravitational constant, Planck.s constant etc.
(4) Dimensionless Constant: Quantities which have constant values and also have no dimensions are called dimensionless constants. Examples are `pi` , e, numbers etc.