Question

A sample of metal weights $210g$ in air, $180g$ in water and $120g$ in an unknown liquid. Then :-

• A. the density of metal is $3g/c{m}^3$
• B. The density of metal is $7g/c{m}^3$
• C. density of metal is $4$ times the density of the unknown liquid
• D. the metal will float in water

Answer 1

Answer: (B)

The density of metal is $7g/c{m}^3$

Metal displaced $210-180=30gms$ of water. As density of water is $1gm/c{m}^3$ volume of the metal is $30c{m}^3$
$\therefore d=210/30=7gm/c{m}^3$