ABSTRACT
This chapter outlines the electromagnetic theory of radiation, and describes how the electromagnetic radiation may be understood as a wave that can be represented by a set of harmonic oscillators. It starts by considering the time-varying electric and magnetic fields that propagate in an empty space, i.e., in the space that does not contain material bodies, but there can be free charges and currents present. The fields propagating in the space satisfy Maxwell's equations, the fundamental laws relating to the electric and magnetic field vectors assembled together into a single set of differential equations. Electromagnetic waves contain and transport energy. The chapter analyzes briefly Maxwell's idea leading to the electromagnetic theory of light. The electromagnetic waves have specific properties, which are determined from Maxwell's equations. Maxwell's theory of electromagnetism shows that the electric and magnetic fields propagate in vacuum as plane waves.
