In the International System of Units, the derived unit of luminous flux; the amount of light that falls on a unit area at unit distance from a source of one candela. Symbol: lm
A measure of the amount of light from a source typically equivalent to the light emitted by one candle
Unit of luminous flux It is the amount of light which falls on one unit area when the surface area is at unit distance from 1 candela
The tubular space in blood vessels, such as the arteries, through which blood travels
A unit of illumination, being the amount of illumination of a unit area of spherical surface, due to a light of unit intensity placed at the center of the sphere
{i} unit for measuring the rate at which light is transmitted (Optics); cavity, hollow space (Anatomy, Botany)
a unit of luminous flux equal to the amount of light given out through a solid angle of 1 steradian by a point source of 1 candela intensity radiating uniformly in all directions
A measure of the amount of light available from a light source equivalent to the light emitted by one candle
(lm) SI unit of luminous flux Radiometrically, it is determined from the radiant power Photometrically, it is the luminous flux emitted within a unit solid angle (one steradian) by a point source having a uniform luminous intensity of one candela
a cavity or passage in a tubular organ; "the lumen of the intestine" a unit of luminous flux equal to the amount of light given out through a solid angle of 1 steradian by a point source of 1 candela intensity radiating uniformly in all directions
Unit of measure representing the total amount of light flux (energy) in any particular situation, e g , from a lamp, through an aperture, etc
The unit of measure for the light energy which flows in air The total light output from electric sources is expressed in lumens A uniform source of one candlepower placed in a sphere emits 12 57 lumens or mean spherical candela equals to 12 57 lumens
The volume enclosed by the endoplasmic reticulum or the mitochondrial inner membrane; the interior space of a tubular organ such as a blood vessel
The unit of luminous flux; the luminous flux on a unit surface all points of which are at unit distance from a point source of one candle
The luminous flux emitted within a unit solid angle (one steradian) by a point source having a uniform luminous intensity of 1 cd
A unit of light flux, being the flux through one square meter of surface the illumination of which is uniform and of unit brightness
a unit of measurement quantifying the amount of light emitted from a light source
The basic unit of measurement for light A dinner candle shines at about 12 lumens A 60-watt Soft White bulb is much more powerful: 855 lumens If a uniform point source of 1 candela is at the center of a sphere of 1-foot radius which has an opening of 1 square foot area at its surface, the quantity of light that passes through is called a lumen The sphere has a total surface area of 12 57 square feet Since, by definition, a lumen flows to each square foot of surface area, a uniform point of 1 candela produces 12 57 lumens The general term applied to families of smaller diameter fluorescent lamps, some of which have built in ballasts and medium screw bases for easy replacement of incandescent lamps
A unit of light power from a light source: the rate at which light falls on one square foot of surface area one foot away from a light source on one candlepower or on candela
The quantity of luminous flux emitted within a unit solid angle (one steradian) by a point source with one candella intensity in all directions
A unit of luminous flux The lumen is equal to the luminous flux radiated into a unit solid angle (steradian) from a small source having a luminous intensity of one candle An ideal source possessing an intensity of one candle in every direction would radiate a total of 46 lumens
Measurement of light output: One lumen is equal to the amount of light emitted by one candle that falls on one square foot of surface located one foot away from one candle
A unit of luminous flux; overall light output; quantity of light, expressed in lumens For example, a dinner candle provides about 12 lumens and a 60-watt soft white incandescent lamps provides about 840 lumens
A photometric unit related to the photopic stimulus of the human fovea It is computed by convolving the photopic response function with the spectral power distribution function Normalization is defined so that the conversion from watts to lumens is 1/683 at the peak sensitivity wavelength of 555 nanometers (See Chapter10 for details )
Often referred to as ANSI lumens when it pertains to projectors Lumens is a measurement of light An ANSI lumen is an average of overall light output as measured in several places at the screen