%0 Journal Article
%T The Third Electromagnetic Constant of an Isotropic Medium:
%A Jose F. Nieves
%A Palash B. Pal
%J Physics
%D 1992
%I arXiv
%R 10.1119/1.17598
%X In addition to the dielectric and magnetic permeability constants, another constant is generally needed to describe the electrodynamic properties of a linear isotropic medium. We discuss why the need for the third constant arises and what sort of physical situations can give rise to a non-zero value for it. This additional constant, which we call the {\em ``Activity Constant''} and denote by $\zeta$, can explain optical activity and other phenomena from a purely macroscopic and phenomenological point of view.
%U http://arxiv.org/abs/hep-ph/9212300v2