Question

When charge is given to a soap bubble it shows

• A. a decrease in size
• B. no change in size
• C. an increase in size
• D. sometimes an increase and sometimes a decreases in size

Answer 1

The correct option is C an increase in size

When external charge is put on the surface of the bubble, it gets distributed uniformly over the entire surface of the bubble, which increases the potential at the surface (with respect to some origin, say the center of the bubble). Since the potential energy of soap bubble is proportional to the surface area of the bubble, to compensate this increased potential energy, the bubble expands.