lumen

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lumen:

see photometryphotometry
, branch of physics dealing with the measurement of the intensity of a source of light, such as an electric lamp, and with the intensity of light such a source may cast on a surface area.
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Lumen

A unit of light from one source. Light falling on 1 square foot of surface of an imaginary sphere having a 1-foot radius around 1 candle.

Lumen

 

the unit of luminous flux in the International System of Units. Symbol, 1m. One lumen is the luminous flux emitted by an isotropic point source in a with a luminous intensity of 1 candela in a solid angle of 1 steradian.

lumen

[′lü·mən]
(anatomy)
The interior space within a tubular structure, such as within a blood vessel, a duct, or the intestine.
(optics)
The unit of luminous flux, equal to the luminous flux emitted within a unit solid angle (1 steradian) from a point source having a uniform intensity of 1 candela, or to the luminous flux received on a unit surface, all points of which are at a unit distance from such a source. Symbolized lm.
(science and technology)
The space within a tube.

lumen (lm)

The SI unit of luminous flux equal to the luminous flux received on a unit surface, all points of which are equidistant from a point source having a uniform intensity of 1 candela.

lumen

A unit of measurement of the light intensity radiating in the air in all directions from a light source. Lumens define "luminous flux," which is energy within the range of frequencies we perceive as light. For example, a wax candle generates about 13 lumens; a 60-watt bulb approximately 800, and a 100-watt bulb 1,600 lumens.

Lumen Ratings for Data Projectors
When choosing a data projector, the lumen rating is an important specification. In a small, dark room, 500 lumens may be ample; however, in a conference room with normal lighting, 1,000 to 2,000 lumens is required. In a large, well-lit room, at least 2,000 lumens is necessary. This rating is derived by taking the average of photometer readings at several points on a full white image on the screen. See lux, ANSI lumen, Lm/W, candela and spectrum.
References in periodicals archive ?
21, 2015 /PRNewswire/ -- Green Lumens LLC will be featured in an upcoming episode of "Innovations with Ed Begley Jr.
The highest performing commercially available single-die LEDs produce up to 186 lumens per watt at 350 milliamps.
LLD is commonly computed as a ratio of mean to initial lumens, where mean lumens are taken to be the lumens produced at 40% of rated life.
Each fiber can deliver about 400 lumens, comparable to the light from a 30-watt incandescent bulb, notes David Beshears, one of the developers.
Lumens can start and stop, previously accomplished only by welding plugs in a secondary operation.
The New York Section of the Illuminating Engineering Society is accepting submission for the 28th Annual Lumen Awards now through January 14, 2006.
8 feet away, and provide 2500 ANSI lumens, 2100 ANSI lumens, and 1500 ANSI lumens, respectively.
Wattage actually measures how much energy a light bulb uses, while lumens measure the bulb's power.
For LEDs this means lumens generated per watt of power consumed will continue to rise at a pace that far outstrips bulb technology, while manufacturing costs should fall precipitously as volumes ramp up.
Independently controlled channels offer 4600 lumens of red (@ 210W), 7600 lumens of green (@ 320W) and 1100 lumens of blue (@ 330W).
Warm white (3000 K) XLamp XM-L LEDs provide up to 113 lumens and 117 lumens per watt and neutral white (4000K) XM-L LEDs provide up to 134 lumens and 138 lumens per watt, both at 350 mA.