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Electric light
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<p>An electric light, lamp, or light bulb is an <a href="/facts/Electrical_component/F3NBVv4Q">electrical component</a> that produces <a href="/facts/Light/jeofpMn4">light</a>. It is the most common form of artificial <a href="/facts/Lighting/Gk54r8xE">lighting</a>. Lamps usually have a base made of <a href="/facts/Ceramic/9JKudpqX">ceramic</a>, metal, glass, or plastic that secures them in the socket of a <a href="/facts/Light_fixture/vjgU4z1f">light fixture</a>, which is also commonly referred to as a 'lamp.' The electrical connection to the socket may be made with a screw-thread base, two metal pins, two metal caps or a <a href="/facts/Bayonet_mount/0QBlN455">bayonet mount</a>. </p><p>The three main categories of electric lights are incandescent lamps, which produce light by a <a href="/facts/Incandescent_light_bulb/31frjg0A">filament</a> heated white-hot by <a href="/facts/Electric_current/Dc1xdnUX">electric current</a>, <a href="/facts/Gas-discharge_lamp/SQPgULuM">gas-discharge lamps</a>, which produce light by means of an <a href="/facts/Electric_arc/1hUPPAG0">electric arc</a> through a gas, such as <a href="/facts/Fluorescent_lamp/R8SlXCyg">fluorescent lamps</a>, and <a href="/facts/LED_lamp/kMsxpkk9">LED lamps</a>, which produce light by a flow of electrons across a <a href="/facts/Band_gap/IjIeh95l">band gap</a> in a <a href="/facts/Semiconductor/zFf3mGTE">semiconductor</a>. </p><p>The <a href="/facts/Efficient_energy_use/8K8vBAVk">energy efficiency</a> of electric lighting has significantly improved since the first demonstrations of arc lamps and incandescent light bulbs in the 19th century. Modern electric <a href="/facts/Light/jeofpMn4">light sources</a> come in a profusion of types and sizes adapted to many applications. Most modern electric lighting is powered by centrally generated electric power, but lighting may also be powered by mobile or standby electric generators or battery systems. <a href="/facts/Electric_battery/bqEpm4ue">Battery</a>-powered light is often reserved for when and where stationary lights fail, often in the form of <a href="/facts/Flashlight/WFx32GbI">flashlights</a> or electric <a href="/facts/Lantern/m6auBTAq">lanterns</a>, as well as in vehicles. </p>