A certain block weighs 15 N in air. But is weighs only 12 N when completely immersed in water. When immersed completely in another liquid, it weighs 13 N. Calculate the relative density of (i) the block and (ii) the liquid.

Explanation

(i) `"Relative density of body"=(W_("air"))/(W_("air")-W_("water"))`
where `W_("air")=15N` (weight of the body in air)
and `W_("water")=12N` (weight of the body in water)
`therefore"R.D"_("block")=(15N)/(15N-12N)=5`
(ii) `"R.D"_(L)=("loss of weight in liquid")/("loss of weight in water")=(15-13)/(15-12)=(2)/(3)`