Question

A soap bubble is given a negative charge. The pressure inside the bubble:

• A. increases
• B. becomes equal to atmospheric pressure
• C. does not change
• D. decreases

Hint:

Remember that increasing the radius of a soap bubble causes the pressure inside it to decrease due to the formula involving surface tension.

Answer 1

The Correct Option is D

When a soap bubble is given a negative charge, the repulsion between the same charges causes the surface area of the bubble to increase. The pressure inside a soap bubble is given by the formula: \[ P = \frac{4T}{r} \] Where \(P\) is the pressure, \(T\) is the surface tension, and \(r\) is the radius of the bubble. As the radius increases due to the charge, the internal pressure of the bubble decreases.