Is the C=εA/d Formula for a Parallel Plate Capacitor an Approximation?

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Discussion Overview

The discussion revolves around the formula C=εA/d for a parallel plate capacitor, specifically questioning whether it is an approximation and the implications of edge effects on its accuracy. The scope includes theoretical considerations and potential refinements to the formula.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions the realism of the formula, suggesting it may rely on assumptions about the size of the plates and the behavior of the electric field at the edges.
  • Another participant asserts that the formula is accurate and challenges the doubt expressed regarding its validity.
  • A different participant acknowledges that edge effects could influence the capacitor's behavior, indicating a concern about the accuracy of the formula.
  • Another response mentions that while edge effects do exist, they may be negligible, referring to this phenomenon as the fringe effect.

Areas of Agreement / Disagreement

Participants express differing views on the accuracy of the formula, with some asserting its validity and others highlighting potential limitations due to edge effects. The discussion remains unresolved regarding the extent of these effects and their significance.

Contextual Notes

Participants note the potential influence of fringe effects and edge behavior on the formula's accuracy, but do not reach a consensus on the implications of these factors.

rshalloo
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Just wondering if the formula C=εA/d is a realistic formula for a parallel plate capacitor, surely its making an approximation about the plates being HUGE or that at the edges the electric field doesn't go in nice straight lines from one plate to the other?

If it is an approximation does anyone know the more accurate formula
 
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Yes, it is an accurate formula. Why do you doubt it?
 
I just thought that effects at the edge of the plate would affect it slightly
 
It does affect. But i guess the error of not taking into account is negligible!
Its called fringe effect in capacitor.
 

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