Question

define relative density . give it mathematical formula.

Answer 1

Relative density is the ratio of the density of an object to the density of water at 4°C. It does not have a unit since it is a ratio.

Relative density = Density of object ÷ Density of water.

Answer 2

Relative density : is the ratio of the density of a substance to the density of a given reference material.

Relative density is also called specific gravity when the reference material will be water the density of water is 1000 kg/ m³

Relative density = density of material / density of reference material 

Specific gravity = density of material / density of water (1000 kg/m³ ) 

It has no units