Question

The weight of an object in air is $25N$ and the weight of that object when submerged in water is $20N$? What is the relative density of the object?

• A. 1.5
• B. 2.5
• C. 5
• D. 6

Answer 1

The correct option is C 5

Apparent weight (W') = Actual weight (W) - Buoyancy (B) where $W=\rho gV$ and $B={\rho }_{w}gV$

$\therefore$ $25=20-B$ $⟹B=5$ N

Relative density $r=\frac{\rho }{{\rho }_w}=\frac{W}{B}=\frac{25}{5}=5.0$