Question

What is relative density?

Answer 1

relative density defined as ratio of its density to that of water at 4 degree centigrade.
OR
Relative density can defined as ratio between mass of substance and mass equal of volume of water at 4 degree centigrade
Relative density = density of substance /density of water
relative density is also called specific density
Relative density has no unit

Answer 2

Relative density of a substance is defined as the ratio of the density of the substance to the density of water