Question

Calculate the amounts of work done in blowing a soap bubble of radius 25mm if surface tension of soap solution 25n\m

Answer 1

Explanation:

Molecules on the surface of a liquid are more energetic than molecules inside. When the radius of the bubble is increased, area of the bubble also increases. Thus the number of molecule occupying the surface increases. This requires external work. By supplying this work, we are increasing the surface energy of the bubble.

Therefore work done is the change in surface energy.

Surface energy = surface tension x surface area.

Change in surface energy = surface tension x change in surface area.