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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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Luminous intensity expressed in candelas. The term refers only to the intensity in a particular direction and by itself does not give an indication of the total light emitted. The candlepower in a given direction from a light source is equal to the illumination in footcandles falling on a surface normal to that direction, multiplied by the square of the distance from the light source in feet. The candlepower is also equal to the illumination of metercandles (lux) multiplied by the square of the distance in meters.

The apparent candlepower is the candlepower of a point source which will produce the same illumination at a given distance as produced by a given light source.

The mean horizontal candlepower is the average candlepower of a light source in the horizontal plane passing through the luminous center of the light source.

The mean spherical candlepower is the average candlepower in all directions from a light source as a center. Since there is a total solid angle of 4π (steradians) emanating from a point, the mean spherical candlepower is equal to the total luminous flux (in lumens) of a light source divided by 4π (steradians). See Luminous intensity, Photometry

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.


Luminous intensity expressed in candelas. Abbreviated cp.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

candlepower (cp)

The luminous intensity of a light source, expressed in candelas. Abbr. cp. Also see apparent candlepower.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.


the luminous intensity of a source of light in a given direction: now expressed in candelas but formerly in terms of the international candle
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005


A unit of measurement of the intensity of a light source, such as a light bulb. The candela rates the light source itself; however, the intensity of light radiating from that source is measured in "lumens." Part of the SI system of measurement, one ordinary wax candle generates approximately one candela (one cd). The term candela means "candle" in Latin, but the measurement was originally defined in the mid-1800s as "candlepower." See lumen, lux, nit and SI.
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References in periodicals archive ?
CandlePower includes WoodWick and Chesapeake Bay Candles, which are in the Yankee Candle family of brands.
Specifications Construction: Frame and Grid: Powder-coated steel: 2.5" square tube uprights and frame Panels and strip Anti-static PVC, 40 mil (panels), 60 shields: mil (strips) Fan Filter Units: 2' x 4' HEPA, 3 speeds (see page 18) Lighting: 2' x 4', 4-tube fluorescent fixture, 3409 candlepower, 120 W, 120-277VAC Power Supply Unit: Switched supply to six-receptacle unit for connection of up to 3 FFUs and lights, plus one non-switched 120V outlet, cord and 3-prong plug.
It wasn't so long ago that flashlights were measured by "candlepower" or candela.
All that was needed were a couple of 400,000 candlepower hand-held spotlights, several specially-designed crates and an ice chest with a few bottles of water.
Many of the animals were only spotted by the reflection of the light on their eyes in the darkness, and the extra candlepower allowed them to make certain of clear shooting backgrounds.
Peak Beam Systems' line of Maxa Beam Searchlights offer an unparalleled 12,000,000 CandlePower output and 3,500 meter range in military-grade housings.
Walking past the mist shrouded Mumbles lighthouse, its vast candlepower sweeping through the cloaking, cloying night, joggers flit past in their all weather gear, some wearing head torches appearing in the distance like huge, bobbing fireflies.
The new LED Hornet is a replacement for a 50-watt MR16 halogen fixture in lumen output and centre beam candlepower.
The Flying Fish Boat Trip aboard the open-deck Blanche W vessel with candlepower searchlights will provide visitors with views of marine life.
This device was a lighting apparatus that had a changeover switch to candlepower in the socket rather than a reinvention of the lamp itself.
The website has the light on whereas the book is driven by candlepower.
"Consumers and the trade have been left in the dark to figure out the difference between candlepower, candela and lumens, among other inconsistent flashlight claims, which left everyone guessing about how to compare one light to another," explains Nario-Redmond.