[[Image:PrismAndLight.jpg|thumb|300px|A beam of white light (entering upwards from the right) is dispersed into its constituent colors by its passage through a [[triangular prism (optics)|prism]]. The fainter beam of white light exiting to the upper right has been reflected (without dispersion) off the first surface of the prism.]]
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[[Image:PrismAndLight.jpg|left|thumb|300px|A beam of white light (entering upwards from the right) is dispersed into its constituent colors by its passage through a [[triangular prism (optics)|prism]]. The fainter beam of white light exiting to the upper right has been reflected (without dispersion) off the first surface of the prism.]]