Question

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 become equal
• 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
• D. there is no flow of air

Answer 1

Answer: (C)

air flows from the smaller bubble to the bigger

Since excess pressure inside an air bubble of radius R is $\frac{4\sigma }{R}$, the smaller bubble has higher pressure. Hence air flows from smaller bubble to larger bubble.