Question

What is the SI unit of relative density?

• A. $gc{m}^{-3}$
• B. $kg{m}^{-3}$
• C. $gc{m}^3$
• D. Unitless

Answer 1

The correct option is D Unitless

Relative density of a substance is a pure ratio of density of the substance to the density of water. Hence, relative density has no unit.