7.1: Electromagnetic (EM) Waves
- Page ID
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Electromagnetic waves (also called electromagnetic radiation) are waves that obey Maxwell's equations. One of the consequences of Maxwell's equations is that there are electromagnetic waves that propagate at \(3\times 10^{8}\text{ m/s}\) in a vacuum. This is precisely the speed of light in a vacuum! Therefore, all light-visible light, ultraviolet radiation, radio waves, microwaves, x-rays, gamma rays, and infrared radiation-is an electromagnetic wave. The difference between these waves is simply in the frequency (\(f\)) or wavelength (\(\lambda\)). Since the frequency times the wavelength (\(f\lambda\)) is equal to the speed of propagation (which for light in a vacuum must be \(3\times 10^{8}\text{ m/s}\)), if you know the frequency, you know the wavelength. This chapter examines propagating electric and magnetic fields and links them to the observable properties of light.