Power in Optics
In optics, or radiometry, the term power sometimes refers to radiant flux, the average rate of energy transport by electromagnetic radiation, measured in watts. In other contexts, it refers to optical power, the ability of a lens or other optical device to focus light. It is measured in dioptres (inverse metres), and equals the inverse of the focal length of the optical device.
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Famous quotes containing the words power in and/or power:
“Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio. A slight acquaintance with numbers will show the immensity of the first power in comparison of the second.”
—Thomas Robert Malthus (1766–1834)
“A seashell should be the crest of England, not only because it represents a power built on the waves, but also the hard finish of the men. The Englishman is finished like a cowry or a murex.”
—Ralph Waldo Emerson (1803–1882)