DETERMINATION OF ELECTRIC FIELD IN TERMS OF CURRENT AND CHARGE BY THE CONTINUITY EQUATION APPROACH

To determine an expression for the electric field in terms of current density and charge density is used the continuity equation approach. In this approach, the expression of electric field using scalar and vector potential relates the charge density and current density. The major consequence of these equations is that they visualize how varying electric fields propagate at the speed of light. In Maxwell's electrodynamics, formulated as it is in terms of charge and current densities, a point charge must be regarded as the limit of an extended charge, when the size goes to zero. Hence, the total electric field at the point P is