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This is a list of sources of light, the visible part of the electromagnetic spectrum.Light sources produce photons from another energy source, such as heat, chemical reactions, or conversion of mass or a different frequency of electromagnetic energy, and include light bulbs and stars like the Sun. Reflectors (such as the moon, cat's eyes, and mirrors) do not actually produce the light that ...
Pages in category "Light sources" The following 61 pages are in this category, out of 61 total. This list may not reflect recent changes. ...
The main source of natural light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.
The color of a light source is determined by the spectrum of the electromagnetic wave's electric field () as it fluctuates at an extremely high frequency. Obtaining a spectrum from time series such as these involves the Fourier transform , and generalizations based on Fourier analysis.
The frequency of light used in the definition corresponds to a wavelength in a vacuum of 555 nm, which is near the peak of the eye's response to light. If the 1 candela source emitted uniformly in all directions, the total radiant flux would be about 18.40 mW, since there are 4 π steradians in a sphere.
Color temperature for white light sources also affects their use for certain applications. The color temperature of a white light source is the temperature in kelvins of a theoretical black body emitter that most closely matches the spectral characteristics (spectral power distribution) of the lamp. An incandescent bulb has a color temperature ...
A directional source (or distant source) uniformly lights a scene from one direction. [4] Unlike a point source, the intensity of light produced by a directional source does not change with distance over the scale of the scene, as the directional source is treated as though it is extremely far away. [4]
A point source is a single identifiable localized source of something. A point source has a negligible extent, distinguishing it from other source geometries. Sources are called point sources because, in mathematical modeling, these sources can usually be approximated as a mathematical point to simplify analysis.