Electromagnetic spectrum
Maxwell's equations united the study of electromagnetism and optics. Light is the relatively narrow frequency band of electromagnetic waves to which our eyes are sensitive. Figure illustrates the spectrum of visible light. Wavelengths are usually measured in units of nanometers (1 nm = 10 −9 m) or in units of angstroms (1Å = 10 −10m). The colors of the visible spectrum stretch from violet, with the shortest length, to red, with the longest wavelength.
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