JEE Main · 2004 · 24 Apr 2004 · Offline · Fluid Mechanics

If two soap bubbles of different radii are connected by a tube,

(A)air flows from the bigger bubble to the smaller bubble till the sizes are interchanged.
(B)air flows from bigger bubble to the smaller bubble till the sizes are interchanged
(C)air flows from the smaller bubble to the bigger.✓ Correct
(D)there is no flow of air.

Answer: (C)

Solution

The excess pressure inside a soap bubble is

\frac{4 T}{r}

, which is larger for a smaller radius. So the small bubble sits at the higher pressure, and when the two are joined by a tube air is driven from the small bubble into the big one; the small bubble shrinks while the larger one grows.

JEE Main · 2004 · 24 Apr 2004 · Offline · Single correct option

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