Pulling apart a charged capacitor and Poynting theorem.

AI Thread Summary
When a parallel plate capacitor with equal and opposite charge densities has its plates separated from distance d to 2d, work is done, resulting in a doubling of electrostatic field energy. The discussion centers on whether Poynting's theorem can be applied to account for this increase in energy. A careful application of Poynting's theorem confirms that it does account for the doubling of electrostatic energy. The relationship between work done and energy stored in the electric field is emphasized. Thus, Poynting's theorem is relevant in analyzing the energy changes in this scenario.
Spinnor
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Suppose we have equal and opposite charge densities on a parallel plate capacitor. Let the plates be separated some small distance d (small when compared with the plate size). Now slowly separate the plates so that their separation is now doubled to 2d. We have done work and the electrostatic field energy has roughly doubled. Should a careful application of Poynting's theorem to this problem account for the doubling of electrostatic energy?

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Spinnor said:
We have done work and the electrostatic field energy has roughly doubled. Should a careful application of Poynting's theorem to this problem account for the doubling of electrostatic energy?
Yes.
 
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