A jar filled with two non mixing liquids 1 and 2 having densities ρ1 and ρ2 respectively. A solid ball, made of a material of density ρ3, is dropped in the jar. It comes to equilibrium in the position shown in the figure. Which of the following is true for ρ1,ρ2 and ρ3 ?
(A)ρ3<ρ1<ρ2
(B)ρ3<ρ2<ρ1
(C)ρ1<ρ2<ρ3
(D)ρ1<ρ3<ρ2✓ Correct
Answer: (D)
Solution
The ball settles at the interface, dipping into liquid 2 but riding on top of liquid 1. Resting on liquid 1 means liquid 1 is lighter than the ball (ρ₁ < ρ₃); failing to sink through liquid 2 means liquid 2 is heavier than the ball (ρ₃ < ρ₂). Liquid 1 itself floats above liquid 2, so ρ₁ < ρ₂. Chaining these gives ρ₁ < ρ₃ < ρ₂.
JEE Main · 2008 · 27 Apr 2008 · Offline · Single correct option