Light.
Electromagnetic radiation that’s visible to the typical unaided human eye.
Visible light consists of electromagnetic energy in wavelengths that range from about 360 nm and 400 nm at the low end to 760 nm and 830 nm at the high end, depending on the person and the intensity of the light in question. (eg: the human eye is better able to detect some colours at low intensities than others)
To be pedantic, the terms “visible light” and “invisible light” are respectively redundant and illogical by this fairly standard definition since light is always visible and non-light EMR is not. But the terms are nonetheless frequently used because they’re useful concepts. In particular, both near-visible infrared and near-visible ultraviolet can be affected and modified optically, unlike other forms of non-light electromagnetic radiation.
cf. electromagnetic radiation, infrared, nm, ultraviolet, wavelength.
Entry last updated 2002-04-27. Term 715 of 1487.
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