Question

A ball is made of a material of density $\rho$ where ${\rho }_{oil}$ < $\rho$ < ${\rho }_{water}$ with ${\rho }_{oil}$ and ${\rho }_{water}$ representing the densities of oil and water, respectively. The oil and water are immiscible. If the above ball is in equilibrium in a mixture of this oil and water, which of the following pictures represents its equilibrium position ?

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

${\rho }_{oil}<\rho <{\rho }_{water}$
Oil is the least dense of them so it should settle at the top with water at the base. Now the ball is denser than oil but less denser than water. So, it will sink through oil but will not sink in water. So it will stay at the oil-water interface.