Subtleties on energy calculations in the image method
Abstract
In this pedagogical work we point out a subtle mistake that can be done by undergraduate or graduate students in the computation of the electrostatic energy of a system containing charges and perfect conductors if they naively use the image method. Specifically, we show that the naive expressions for the electrostatic energy for these systems obtained directly from the image method are wrong by a factor 1/2. We start our discussion with well known examples, namely, point charge-perfectly conducting wall and point charge-perfectly conducting sphere and then proceed to the demonstration of general results, valid for conductors of arbitrary shapes.
Keywords
Cite
@article{arxiv.0903.4497,
title = {Subtleties on energy calculations in the image method},
author = {M. M. Taddei and T. N. C. Mendes and C. Farina},
journal= {arXiv preprint arXiv:0903.4497},
year = {2012}
}
Comments
9 pages, 2 figures; Major change in this version: subsection added to Sect.4 (theorem generalization). Minor changes: title replaced; corrections to the English; some explanatory comments added