Elementary Introduction to Electrodynamics

Objectionable examples of time-varying electromagnetic fields occurring in elementary textbooks are pointed out and the difficulties arising in connection with them are discussed. The interdependence of spatial and time variations of the electromagnetic fields is recalled. As an illustration, two simple examples are given to show how the variation of fields with time is automatically determined by the wave equation and initial spatial distribution. It is suggested that only fields which satisfy the wave equation be used in textbooks.