Question

what is the SI unit of relative density​

Answer 1

Relative density doesn't have any S.I. unit. Relative density is expressed in the form of ratio.

Answer 2

Answer:

Relative density is the ratio of density of a substance to the density of water.

The SI unit of Relative density is nothing beacause both the numerator and Denominator has same SI in the ratio form.Hence it gets cancelled.