MCQ
A soap bubble is given negative charge, its radius will:
- AIncrease
- BDecrease
- CRemain unchanged
- DFluctuate
✓
Answer
- Increase
Explanation:
The charge will be distributed uniformly over the surface of the bubble by symmetry.
As we know, they want to step much farther apart, as charges repel, the only path outward, taking with them the soap surface.
At the same point, the rise in the restored force of the soap film (surface tension) would be equal and contrary to the electrostatic force, which will result in a new (larger) radius of equilibrium.
Because of the ionic similarities, this can happen to both positive and negatively charged bubbles.Therefore, when a negative charge is given to the soap bubble, then its radius will increase.
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