Answers

2015-09-28T22:46:41+05:30
Relative density is the ratio of density of a substance and density of water.

R.D.= \frac{Density\ of\ material}{Density\ of\ water}

It's a number. It has no unit.
0
2015-09-29T20:12:27+05:30
Its the ratio of density of substance to density of water at 4 degree celsius 
0