Question

The weight of a solid is 80g in air and 50g in a liquid of relative density 1.5. Calculate the relative density of the solid.

• A. 2
• B. 6
• C. 8
• D. 4

Answer 1

The correct option is D

4

Loss of weight of solid in liquid = (80-50)g = 30g

Weight of equal volume of liquid by Archimedes principle = 30g

If the liquid displaced has a volume of $Vc{m}^3$, then it's weight $=V\times 1.5=30g$

Therefore, $V=20c{m}^3$

Since solid is completely immersed in liquid, so volume of solid = V

The volume of water that will be displaced by same solid $=20c{m}^3$

Therefore weight of this displaced water = 20g

So we have specific gravity of solid = weight of solid in air/weight of water displaced $=\frac{80g}{20g}=4$