Abstract: An electromagnetic field can exist even in the absence of charges. Electromagnetic fields occurring in vacuum in the absence of charges are called electromagnetic waves. This chapter reviews the properties of such fields. It discusses the equations determination of the potentials of electromagnetic waves. The equation that determines the potential of electromagnetic waves is called d'Alembert's equation or the wave equation. The chapter discusses the special case of electromagnetic waves in which the field depends only on one coordinate and on the time). Such waves are said to be plane. An important special case of electromagnetic waves is a wave in which the field is a simply periodic function of the time. Such a wave is said to be monochromatic plane wave. All quantities, such as potentials and field components, in a monochromatic wave depend on the time through a factor of the form cos (Ωt+α). The quantity Ω is called the angular frequency of the wave. Every wave can be subjected to the process of spectral resolution, that is, it can be represented as a superposition of monochromatic waves with various frequencies. The character of this expansion varies according to the character of the time dependence of the field. The chapter further discusses partially polarized light, geometrical optics, Fresnel diffraction, Fraunhofer diffraction, and the characteristic vibrations of a free electromagnetic field.
Publication Year: 1972
Publication Date: 1972-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 8
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