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Topic: Luminous intensity

Related Topics

Luminous flux

Intensity

Luminous efficacy

Photometry (optics)

Candela

Radiant intensity

Lumen (unit)

Luminance

Lux

Luminosity

Radiant energy

Light

Steradian

SI unit

SI

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	Luminous intensity - Wikipedia, the free encyclopedia
		Luminous intensity is a measure of the perceived power emitted by a light source in a particular direction.
		Luminous intensity should not be confused with luminous flux, which is the total perceived power emitted across all directions.
		Luminous intensity is not the same as the radiant intensity, the corresponding objective physical quantity.
	en.wikipedia.org /wiki/Luminous_intensity (210 words)

	Intensity - Wikipedia, the free encyclopedia
		In physics, intensity is a measure of the time-averaged energy flux.
		To find the intensity, take the energy density (that is, the energy per unit volume) and multiply it by the velocity at which the energy is moving.
		In physics, the word "intensity" is not synonymous with "strength", "amplitude", or "level", as it sometimes is in colloquial speech.
	en.wikipedia.org /wiki/Intensity (342 words)

	Untitled Document
		A unit of luminous intensity equal to 1/60th of the normal intensity of one square centimeter of a flbody radiating at the temperature of solidification of platinum.
		Luminous Intensity is equal to the amount of luminous flux emitted into a very small solid angle at a defined angular orientation from the light source.
		The measurement for luminous intensity is the lumen or candela.
	www.ddp-leds.com /appnotes/app_notes_gloss.asp (1299 words)

	Encyclopedia: Luminous intensity
		It is worth noting that luminous intensity (and other derived quantities) is not an "objective" physical quantity but depends on the physiology of the human eye, especially its sensitivity to light of different frequencies.
		Luminous flux is a measure of the energy emitted by a light source in all directions.
		Luminous efficiency is a measure of the proportion of the energy supplied to a lamp that is converted into light energy.
	www.nationmaster.com /encyclopedia/Luminous-intensity (706 words)

	Lighting definitions
		One lumen is the luminous flux of the uniform point light source that has luminous intensity of 1 candela and is contained in one unit of spatial angle (or 1 steradian).
		Luminous intensity is the ability to emit light into a given direction, or it is the luminous flux that is radiated by the light source in a given direction within the unit of the spatial angel.
		Luminance L is the luminous intensity emitted by the surface area of 1 cm² (or 1 m²) of the light source.
	home.tir.com /~ms/lightingdefinitions/lightingdefinitions.html (365 words)

	Luminous Intensity \| Candlepower \| Candle \| Hefner Unit \| Hefner Candle \| Violle
		The luminous intensity is the luminous flux emitted from a point per unit solid angle into a particular direction.
		The luminous intensity is the official base unit for light.
		The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10
	www.schorsch.com /kbase/glossary/luminous_intensity.html (207 words)

	Candela
		Historically, the engineers' unit of power, the watt, has been separated from the unit of luminous intensity, which is also a form of power, because the eye has a varying sensitivity over the visual spectrum, being relatively insensitive to blue and to red light.
		Luminous emission is not the same as the perceived brightness of the source when you look at it.
		The luminous intensity of a "white" light source is defined by multiplying the watts emitted at each wavelength by the efficiency of that wavelength in exciting the eye, relative to the efficiency at 555 nm.
	www.electro-optical.com /whitepapers/candela.htm (1466 words)

	Does higher luminous intensity mean higher light output? \| LED Lighting Systems \| Lighting Answers \| NLPIP
		Cosine distribution - A property of a light source such that its luminous intensity in a particular direction is proportional to the cosine of the angle from the normal to the source.
		Luminous intensity is a function of the angle from which an LED is seen, so this value should be considered carefully when used to characterize the light output of a particular LED.
		Two LEDs with the same luminous flux output can have very different peak luminous intensities, if they are designed to produce different beam angles.
	www.lrc.rpi.edu /programs/NLPIP/lightingAnswers/LED/luminousIntensityLightOutput.asp (584 words)

	What are the IESNA cutoff classifications? \| Light Pollution \| Lighting Answers \| NLPIP
		Luminous intensity - The luminous flux on a small surface centered on and normal to the direction divided by the solid angle (in steradians) that the surface subtends at the source.
		Luminous intensity can be expressed in candelas or in lumens per steradian.
		Full cutoff—The luminous intensity (in candelas) at or above an angle of 90° above nadir is zero, and the luminous intensity (in candelas) at or above a vertical angle of 80° above nadir does not numerically exceed 10% of the luminous flux (in lumens) of the lamp or lamps in the luminaire.
	www.lrc.rpi.edu /programs/nlpip/lightinganswers/lightpollution/cutoffClassifications.asp (1008 words)

	Luminous Flux \| Lumen
		As with luminous intensity, the luminous flux of light with other wavelengths can be calculated using the CIE photometric curve.
		The luminous flux is a very basic unit of measurement for light.
		If a uniform point light source of 1 cd luminous intensity (about the intensity of a normal wax candle!) is positioned at the center of a sphere of 1 m radius, then every area of 1 m
	www.schorsch.com /kbase/glossary/luminous_flux.html (180 words)

	luminous intensity - a Whatis.com definition (Site not responding. Last check: 2007-10-08)
		Luminous intensity is an expression of the amount of light power emanating from a point source within a solid angle of one steradian.
		A frequency of 540 THz corresponds to a wavelength of about 555 nanometers (nm), which is in the middle of the visible-light spectrum, and is generally accepted as the frequency and wavelength at which the average human eye is most sensitive.
		Late in the 20th century, the candela was defined and adopted as the standard unit of luminous intensity.
	whatis.techtarget.com /definition/0,,sid9_gci553541,00.html (275 words)

	Luminous Flux
		The luminous flux is the part of the power which is perceived as light by the human eye, and the figure 683 lumens/watt is based upon the sensitivity of the eye at 555 nm, the peak efficiency of the photopic (daylight) vision curve.
		Thus, luminous flux is a weighted average of the Radiant Flux in the visible spectrum.
		The lumen is the unit of luminous flux, and is defined in terms of the candela, an SI base unit like the meter or second.
	hyperphysics.phy-astr.gsu.edu /hbase/vision/lumpow.html (773 words)

	Volpe Center: Operator Performance and Safety Analysis Division (Site not responding. Last check: 2007-10-08)
		The luminous intensity of a steady burn light source is expressed in units of "candela." The optical power output of a flashing light is measured differently than a steady burn light because of flash rate effects and the duration of each flash.
		The apparent luminous intensity of a flashing light with a rating of 100 effective candela is such that it is seen to be as bright as a 100 candela steady burn light, when viewed from the same distance or having the same visual range.
		The minimum luminous intensities for flashing lights on obstructions which are greater than 15 m (50 ft) in diameter are not specified; however, a range of visibility of 1 nautical mile is required.
	www.volpe.dot.gov /opsad/lcnsrpt/lcnsch4.html (4528 words)

	[No title]
		Luminous intensity is a property of the source, not the light collected some distance from the source.
		Luminance is a property of reflective and glowing surfaces.
		The luminous intensity in the direction of the observer must take the cosine rule into account (we don’t have to correct for distance yet, since luminous intensity is a property of the source, without regard to distance).
	www.psych.upenn.edu /backuslab/vss2002/PhysicalModel_v03.doc (895 words)

	luminous intensity -- Encyclopædia Britannica
		The unit for the quantity of light flowing from a source in any one second (the luminous power, or luminous flux) is called the lumen.
		The candela is defined as the luminous intensity in a given direction of a source that emits monochromatic radiation at a frequency of 540 1012 hertz and that has a radiant intensity in the same direction of 1/683 watt per steradian (unit solid angle).
		The luminous intensity of a light, or its candlepower, is expressed in international units called candelas.
	www.britannica.com /eb/article-9049341 (869 words)

	United States Patent Application: 0020149024
		By controlling a ratio of a hole concentration of the p-type layer and an electron concentration of the n-type layer approximates to 1, luminous intensity of the device is improved.
		A luminous intensity of the device is strongly related to a composition ratio x of aluminum (Al) in Al.sub.xGa.sub.1-xN barrier layer.
		9 is a graph showing the correlation of an electron concentration and a luminous intensity of the n-contact layer in accordance with the third embodiment of the present invention.
	appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/PTO/search-adv.html&r=1&f=G&l=50&d=PG01&p=1&S1=20020149024&OS=20020149024&RS= (9330 words)

	Glare (Site not responding. Last check: 2007-10-08)
		Luminous Intensity is the amount of light a luminaire emits in a given direction.
		The candela is the unit of measure of luminous intensity.
		What we do know, though, is that brightness is related to luminous intensity and also to viewing distance (the closer we are, the brighter it appears).
	www.lithonia.com /cutofflighting/Glare.htm (230 words)

	Comparison Test - Lynx Roadstuds and Roadsafety Products
		The graphs in illustration 1 prove that the drop of the coefficient of luminous intensity clearly depends on the period of use, i.e.
		If these minulnum coefficients of luminous intensity are taken as a basis for the values of uncleaned reflectors, a minimum coefficient of 250 mcd/lx must be assumed for cleaned reflectors in working condition.
		Their coefficients of luminous intensity in a new state are 40 to 50 percent lower than those of rectangular reflectors of the same type.
	www.lynxroadstuds.co.za /test_reflector.htm (1671 words)

	Radiant/Luminous Flux and Radiant/Luminous Intensity (Site not responding. Last check: 2007-10-08)
		Radiant/Luminous Intensity is the amount of emitted optical power generated by a light source in a specific direction and conical shape angle directed toward the observer.
		The unit for Radiant Flux is watt (W), and Luminous Flux is lumen(lm).
		The unit for Radiant Intensity is Watt/steradian (W/sr) and Luminous Intensity is Lumens/steradian (lm/sr).
	www.marktechopto.com /products/radiant_flux.cfm (288 words)

	New Page 1 (Site not responding. Last check: 2007-10-08)
		Luminous flux is the rate that light is emmited from a source.
		The symbol of luminous flux is P. The unit that luminous flux is measured in is lumens.
		The first lamp emits a luminous flux of 2145lm is 4.3m from the wood.
	grassroots.brunnet.net /riverviewhs/light/Theory.htm (852 words)

	Mine Safety and Health Administration (MSHA) - Code of Federal Regulations - 30 CFR 75.1719-3
		In areas of working places specified in §75.1719-1(e)(4) luminous intensity measurements may be made at any time longwall or shortwall mining equipment is operated except that when measurements are made in the vicinity of shearers, plows, or continuous miners, the equipment shall be idle while measurements are being made.
		In areas of working places specified in §75.1719-1(e)(6), luminous intensity measurements of a coal surface shall be made with the machine idle and located in the approximate center of the working place with the appropriate end toward the face and not less than 9 feet nor more than 10 feet from the face.
		Measurements shall be taken with the photometer held approximately perpendicular to the surface being measured and a sufficient distance from the surface to allow the light sensing element in the instrument to receive reflected light from a field of not less than 3 nor more than 5 square feet.
	www.msha.gov /30CFR/75.1719-3.htm (416 words)

	Physics Tutoring: Electromagnetic Waves (Site not responding. Last check: 2007-10-08)
		luminosity factor: The ratio of the luminous flux in lumens emitted by a source at a particular wavelength to the corresponding radian flux, in watts, at the same wavelength this is a measure of the visual sensitivity of the eye.
		luminous coefficient: A measure of the fraction of the radian power of a light source which contributes to its luminous properties, equal to the average of the luminosity function at various wavelengths, weighted according to the spectral intensity of the source.
		luminous intensity: The luminous flux incident on a small surface which lies in a specified direction from a light source and is normal to this direction, divided by the solid angle (in steradian) which the surface subtends at the source of light.
	www.slcc.edu /schools/hum_sci/physics/tutor/2220/em_waves (1034 words)

	Terms
		The quantity of luminous flux emitted within a unit solid angle (one steradian) by a point source with one candella intensity in all directions.
		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.
		Plots of luminous intensity, called candlepower distribution curves, are used to indicate the intensity of distribution characteristics of reflector-type lamps.
	www.razlight.com /Terms.htm (273 words)

	Power Per Unit Area of Surface
		In radiometry the surface areance may be called irradiance and luminous areance may be called illuminance.
		The nit is the unit of luminance and is defined as a candela per square meter.
		The standard symbol for the luminance in nits is L
	hyperphysics.phy-astr.gsu.edu /hbase/vision/areance.html (223 words)

	PHOTOMETRIC TERMS - A SUMMARY (Site not responding. Last check: 2007-10-08)
		The unit of luminous flux = lumen = 1/685 Watts @ 555 nm.
		Since 100 candles is 100 lumens/steradian, and one steradian for this sphere has an area of 20cm x 20cm = 400 cm², the area in question is 240/400=0.6 steradians, and the number of lumens passing through is 0.6 x 100 = 60 lumens.
		Luminance (brightness) in a given direction = luminous intensity emitted per unit area per steradian of solid angle of the receiver = candles/cm²
	vsg.cape.com /~pbaum/flux.htm (262 words)

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