Density

Density of a substance is defined as mass per unit volume of the substance. It is denoted by ρ.

If M be the mass of the substance of volume V, then density of that substance is given by

Relative density of a substance is defined as the ratio of the density of that substance to the density of water at 4⁰ C.

It has no unit and no dimensions. It is a positive scalar quantity.

The density of water at 4⁰ C is maximum and equal to 1000 kg/m³.

Density and Relative Density