question_answer

If two soap bubbles of different radii are connected by a tube                       [AIEEE 2004]

A)  air flows 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

Correct Answer: C

Solution :

[c] The excess pressure inside the soap bubble is inversely proportional to radius of soap bubble i.e.,where, r is the radius of bubble. It follows that pressure inside a smaller bubble is greater than that inside a bigger bubble.

Thus, if these two bubbles are connected by a tube, air will flow from smaller bubble to bigger bubble and the bigger bubble grows at the expense of the smaller one.

(for soap bubble)