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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 ...
In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. [ 4 ][ 5 ] In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum, and polarization.
An electric light, lamp, or light bulb is an electrical component that produces light. It is the most common form of artificial lighting. Lamps usually have a base made of ceramic, metal, glass, or plastic which secures the lamp in the socket of a light fixture, which is often called a "lamp" as well. The electrical connection to the socket may ...
Illuminated cherry blossoms, light from the shop windows, and Japanese lantern at night in Ise, Mie, Japan. Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing ...
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow.
1835 James Bowman Lindsay demonstrates a light bulb based electric lighting system to the citizens of Dundee. 1841 Arc-lighting is used as experimental public lighting in Paris. 1853 Ignacy Łukasiewicz invents the modern kerosene lamp. 1856 glassblower Heinrich Geissler confines the electric arc in a Geissler tube.
A sodium-vapor lamp is a gas-discharge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm. Two varieties of such lamps exist: low pressure and high pressure. Low-pressure sodium lamps are highly efficient electrical light sources, but their yellow light restricts applications to outdoor ...
Color temperature is a parameter describing the color of a visible light source by comparing it to the color of light emitted by an idealized opaque, non-reflective body. The temperature of the ideal emitter that matches the color most closely is defined as the color temperature of the original visible light source.