Question

A soap bubble of radius 'R' is blown. After heating the solution, a second bubble of radius '2R' is blown. The work required to blow the second bubble in comparison to that required for the first bubble is ______.

Options

• slightly more than 4 times

• slightly less than 4 times

• slightly less than double

• double

Answer 1

A soap bubble of radius 'R' is blown. After heating the solution, a second bubble of radius '2R' is blown. The work required to blow the second bubble in comparison to that required for the first bubble is slightly less than 4 times.

Explanation:

Work done W = 8πR²T

If radius is doubled, the work done will become four times provided surface tension T remains constant. But if the solution is heated, there is some decrease in surface tension and hence the work done will be slightly less than four times.