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Q & A: charge neutrality in capacitors

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Most recent answer: 04/05/2011
Q:
If a capacitor has plates of unequal area will it be the charge on opposite plates that is equal and opposite or the charge density?
- Niharika (age 18)
India
A:
It will be the charges that are equal and opposite, not the charge densities. If the total charge didn't add up to zero, then there would be a strong long-range electrostatic force pulling in whichever sign of charge was needed to bring the net charge to zero.

In the lab, we often work with such asymmetrical capacitors, so this is not just a theoretical conclusion.

Mike W.

(published on 04/05/2011)

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