Question

The adjoining diagram shows three soap bubbles A, B and C prepared by blowing the capillary tube fitted with stop cocks, $S_1$,$S_2$ and $S_3$. With stop cock S closed and stop cocks $S_1$, $S_2$ and $S_3$ opened

[CPMT 1988]

• A. B will start collapsing with volumes of A and C ncreasing
• B. C will start collapsing with volumes of A and B increasing
• C. C and A both will start collapsing with the volume of B increasing
• D. Volumes of A, B and C will become equal at equilibrium

Answer 1

The correct option is C

C and A both will start collapsing with the volume of B increasing

Excess pressure inside soap bubble is inversely proportional to the radius of bubble i.e. $△P\propto \frac{1}{r}$

This means that bubbles A and C posses greater pressure inside it than B. So the air will move from A and C towards B.