Question

explain density and relative density and write their formulae

Answer 1

density is the mass per unit volume.
relative density is the density of the substance to the density of water.
density=mass/volume
relative density =density of substance/density of water

Answer 2

Density of a material is equal to its mass per unit volume.It can be expressed as density=mass/volume
Density is a physical quantity with a magnitude that can be measured.Its SI unit is kilograms per cubic metre.
Relative density is also called specific gravity(SG).Relative density is a number without units.The relative density of water is 1.Relative density=density of substance/density of water.