Induced electric and magnetic fields

Abstract

Abstract In this chapter it is shown that a time-varying magnetic field will give rise to a time-varying electric field and a time-varying electric field will give rise to a time-varying magnetic field. Thus when the fields vary with time it is no longer possible to separate electricity and magnetism as was possible for static fields. Faraday’s law, which governs the generation of an electric field by a time-varying magnetic field, will give rise to electric fields in the form of closed loops which can penetrate conductors, unlike the static electric fields dealt with in Chapter 2. Thus the generation of an electrical current within a living biological cell is often accomplished by applying an external time-varying magnetic field. The realization that a time-varying electric field will generate a magnetic field enabled James Clerk Maxwell to formulate a set of equations called the Maxwell equations that govern electric and magnetic fields under any circumstances.