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Legend:γ = Gamma raysHX = Hard X-raysSX = Soft X-RaysEUV = Extreme ultravioletNUV = Near ultravioletVisible lightNIR = Near infraredMIR = Moderate infraredFIR = Far infraredRadio waves:EHF = Extremely high frequency (Microwaves)SHF = Super high frequency (Microwaves)UHF = Ultrahigh frequencyVHF = Very high frequencyHF = High frequencyMF = Medium frequencyLF = Low frequencyVLF = Very low frequencyVF = Voice frequencyELF = Extremely low frequency
Electromagnetic waves were first predicted by James Clerk Maxwell and subsequently confirmed by Heinrich Hertz. Maxwell derived a wave form of the electric and magnetic equations, revealing the wave-like nature of electric and magnetic fields, and their symmetry. Because the speed of EM waves predicted by the wave equation coincided with the measured speed of light, Maxwell concluded that light itself is an EM wave.According to Maxwell's equations, a time-varying electric field generates a magnetic field and vice versa. Therefore, as an oscillating electric field generates an oscillating magnetic field, the magnetic field in turn generates an oscillating electric field, and so on. These oscillating fields together form an electromagnetic wave.A quantum theory of the interaction between electromagnetic radiation and matter such as electrons is described by the theory of quantum electrodynamics.Quote[attachment=1655]Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This diagram shows a plane linearly polarised wave propagating from left to right.
[attachment=1655]Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This diagram shows a plane linearly polarised wave propagating from left to right.