J. Slisko et Ra. Britoorta, ON APPROXIMATE FORMULAS FOR THE ELECTROSTATIC FORCE BETWEEN 2 CONDUCTING SPHERES, American journal of physics, 66(4), 1998, pp. 352-355
A series expression for the electrostatic force between two charged co
nducting spheres having equal radii and charges is derived using the m
ethod of electrical images. This expression is a special case of that
for two spheres with arbitrary charges and radii, found by Maxwell usi
ng zonal harmonics, Keeping in mind the use of approximate formulas fo
r the interpretation of classroom measurements of the electrostatic fo
rce between spheres, we comment on two incorrect approximate formulas
and examine the contribution of the first few non-Coulomb terms of the
comet formula by comparing with values obtained using a computational
approach. (C) 1998 American Association of Physics Teachers.