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Topic: Radiant flux

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	Radiant energy Summary
		The quantity of radiant energy may be calculated by integrating radiant flux (or power) with respect to time and, like all forms of energy, its SI unit is the joule.
		Radiant energy is produced in the sun as a result of nuclear fusion.
		Since radiant energy is really just electromagnetic radiation under another name, it is the basis of a wide range of communication technologies using radiofrequency and microwave radiation.
	www.bookrags.com /Radiant_energy (1662 words)

	Radiant energy - Wikipedia, the free encyclopedia
		The quantity of radiant energy may be calculated by integrating radiant power with respect to time and, like all forms of energy, its SI unit is the joule.
		The radiation emitted by radiating bodies is concentrated in certain portions of the electromagnetic spectrum.
		Radiant energy may originate in a body or be reflected from another body (in which case it may be refracted or otherwise modified).
	en.wikipedia.org /wiki/Radiant_energy (607 words)

	Photometry (optics) - Wikipedia, the free encyclopedia
		A 1000 watt space heater may put out a great deal of radiant flux (1000 watts, in fact), but as a light source it puts out very few lumens (because most of the energy is in the infrared, leaving only a dim red glow in the visible).
		The lumen is defined as amount of light given into one steradian by point source of one candela strength; while the candela, a base SI unit, is defined as the luminous intensity of a source of monochromatic radiation, of frequency 540 terahertz, and a radiant intensity of 1/683 watts per steradian.
		One watt of infrared radiation (which is where most of the radiation from an incandescent bulb falls) is worth zero lumens.
	en.wikipedia.org /wiki/Photometry_(optics) (858 words)

	[No title] (Site not responding. Last check: 2007-11-01)
		The definition of radiant exitance is: EMBED Equation.2 (5) where F is the radiant flux leaving the point and dA is the differential area surrounding the point.
		It varies not only with wavelength but also with the amount of radiant flux, whether the light is constant or flickering, the spatial complexity of the scene being perceived, the adaptation of the iris and retina, the psychological and physiological state of the observer, and a host of other variables.
		Illuminance is the photometric equivalent of irradiance, whereas luminous exitance is the photometric equivalent of radiant exitance.
	www.ledalite.com /download/white/photomet.doc (3840 words)

	Radiant/Luminous Flux and Radiant/Luminous Intensity (Site not responding. Last check: 2007-11-01)
		Stated briefly, Radiant/Luminous Flux represents the total emitted optical power generated by a light source that is collected and measured with no regard to the direction of the flux.
		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)

	LEDs Magazine - Radiometric and Photometric terms
		Radiometry and radiometric units such as radiant flux relate to properties associated with the energy of electromagnetic radiation (which for LEDs we'll refer to as "light" - this term covers visible light, as well as UV and IR radiation).
		The radiant flux or radiant power of a light-emitting body is the total rate of flow of emitted light i.e.
		Illuminance is the density of the luminous flux incident on a surface.
	ledsmagazine.com /articles/features/1/1/11/1 (518 words)

	Lighting Design Lab Lighting Glossary
		For daylighting, this is the quotient of visible flux incident on a surface to radiant flux on that surface.
		The ratio of radiance (for directional emissivity) or radiant exitance (for hemispherical emissivity) of an element of surface on a temperature radiator to that of a flbody at the same temperature.
		Radiation with wavelengths too long to be perceived by the human eye (that is, longer than 0.77 microns) and less than 1,000 microns.
	lightingdesignlab.com /library/glossary.htm (2124 words)

	Color Option Vinyl Backed Cocoa Matting Flammability Test Results
		The imposed radiant flux simulates thermal radiation levels likely to impinge on the floor of a corridor whose upper surfaces are heated by flames and/or hoe gases from a fully developed fire in an adjacent room or compartment.
		A gas/air fueled radiant heat energy panel is mounted in the chamber at a 30° angle to the horizontal specimen plane.
		Critical radiant flux of 0.5 ± 0.02 watts per square centimeter is measured at a distance of 40 centimeters from the 0 end, indicated proper operation of the test apparatus.
	www.thematking.com /technical_data/testresults/cocoa-color-opt/test-results.htm (758 words)

	Concepts of Hydrologic Optics
		Now consider radiant flux not just per unit solid angle at a point in space, but in the area of a plane at right angles to the direction of flow.
		RADIANCE (L)- radiance at a point in space is radiant flux at that point in a given direction per unit solid angle per unit area at right angles to the direction of propagation.
		Surface Radiance- radiant flux emitted in a given direction per unit solid angle per unit projected area of a surface
	www.usm.edu /marine/syllabus/MAR602lecture2-2002.htm (869 words)

	International Light - Glossary
		The flux per unit solid angle leaving or entering a surface is proportional to the cosine of the angle with respect to the normal to the surface.
		The ratio of the reflected flux to the incident flux from a surface.
		A condition wherein the radiant flux density exceeds either or the capacity of a photodetector to emit electrons in a linear relationship to the incident flux and/or the current produced by the detector exceeds the capacity of the electronics to measure the current in a linear fashion.
	www.intl-light.com /library/glossary (3699 words)

	Calibration & Certification by R. A. Electrical Services
		The flux per unit solid angle leaving or entering a surface is proportional to the cosine of the angle with respect to the normal to the surface.
		The ratio of the reflected flux to the incident flux from a surface.
		A condition wherein the radiant flux density exceeds either or the capacity of a photodetector to emit electrons in a linear relationship to the incident flux and/or the current produced by the detector exceeds the capacity of the electronics to measure the current in a linear fashion.
	www.raelectrical.com /about_us/light-glossary.htm (3545 words)

	Captec Advantage
		The sensitive element of the Captec radiant flux sensor is self generating planar thermopile incorporated into a thin heterogenous multilayer structure designed to convert the thermal radiation absorbed or emitted by the sensing area into a tangential temperature gradient.
		Since the sensitivity is the same for radiation absorption or emission and not dependent on the sensor temperature, the radiant flux sensor requires no temperature compensation, special referring junction or signal conditioning.
		Radiant flux sensors are ideal in the special case where energy transfer through radiation is of prime importance.
	members.aol.com /desmondint/Captec2.html (516 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.
		For instance, the Luminous Flux for a 100W incandescent lamp is approximately 1700 lm.
	hyperphysics.phy-astr.gsu.edu /hbase/vision/lumpow.html (781 words)

	PSL - SCE - Projects - TOA (Site not responding. Last check: 2007-11-01)
		Radiant flux is a measurement of power per unit area.
		Radiant flux is derived from radiance, which is the amount of radiant energy per unit time that is emitted from a unit area of surface in a specified direction.
		Radiance will be referred to in this report periodically, but the primary product to be concerned with is radiant flux.
	www.psl.nmsu.edu /sce/projects/toa/intro.php (369 words)

	1.6 Definition of Radiometry (Site not responding. Last check: 2007-11-01)
		Radiometry is used for physical measurement of a wide range of radiation from x-ray to radio wave, while photometry corresponds to the human perception of visible light based on the human eye's sensitivity as shown in Figure 1.6.1.
		Radiant energy is defined as the energy carried by electro- magnetic radiation and expressed in the unit of joule (J).
		Radiant flux is radiant energy transmitted as a radial direction per unit time and expressed in a unit of watt (W).
	www.profc.udec.cl /~gabriel/tutoriales/rsnote/cp1/cp1-6.htm (206 words)

	Radiant Flux (Site not responding. Last check: 2007-11-01)
		A radiant flux of 1 W means that a source produces 1 Joule every second.
		So we can reasonably assume that the Flux output for a standard lamp is restricted to be in the optical range, and in doing so we may take the nominal wattage as our radiant flux.
		That is, a 60 W incandescent lamp would have a radiant flux of 60 W, and a 250 W Mercury vapor lamp would have a radiant flux of 250 W. The radiant radiant flux must be factored by the sensitivity of the human eye to determine luminous flux in lumens.
	hyperphysics.phy-astr.gsu.edu /hbase/vision/radiant.html (245 words)

	Schwank Infra-red Heaters - Trade Article
		Determine a suitable method to measure the total useful radiant output from an infrared tube heater which will apply equally well to all types of heaters and be accurate, easy to perform and cost effective.
		A thorough understanding of radiant heat transfer was used to determine possible methods to determine the radiant component of the heat transfer from infrared tube heaters.
		Calculations are made of the radiant flux emanating from these sections to determine the radiance distribution and total energy flux from the section.
	www.schwankheaters.com /html/tr-gri5092.html (1659 words)

	NIST Total Spectral Radiant Flux Scale (Site not responding. Last check: 2007-11-01)
		Total spectral radiant flux is the geometrically total radiant flux of a given bandwidth at a given wavelength.
		The total spectral radiant flux is commonly measured using an integrating sphere equipped with a spectroradiometer.
		When the total spectral radiant flux is established in the near future, NIST plans to provide calibration services for this quantity from the near UV to near IR region.
	physics.nist.gov /Divisions/Div844/facilities/photo/Projects/spectral_flux.htm (287 words)

	Radiant Flux Density \| Irradiance \| Radiant Exitance
		Radiant emittance is an old term for radiant exitance.
		The radiant flux per unit area at a point on a surface, where the surface can be real or imaginary (a mathematical plane).
		Radiant exitance is the total amount of radiative flux leaving a point on a surface into all directions above the surface.
	www.schorsch.com /kbase/glossary/irradiance.html (142 words)

	Captec
		Radiant fluxmeter (or sensor of radiant flow) allows to measure exchange by radiation between a system and its environment.
		The active radiant fluxmeter is a radiant fluxmeter coupled with a heater that permits it to maintain the temperature of the sensor.
		The double sided radiant flux sensor permits to compare the radiant flux absorbed or emitted in both directions which in fact allows to measure the net radiant flux.
	home.nordnet.fr /~pithery/english/catalogue.htm (329 words)

	Introduction – Enhanced Night Visibility Volume XVII VES Characterization – December 2005
		The luminous flux, measured in lumens (lm), is the radiant flux of a source evaluated in terms of the human visual response.
		The density of the flux falling on a surface is defined as the irradiance or the illuminance.
		The flux reflected or emitted from a surface or through a projected area that is propagated in a given direction per unit solid angle is defined as the radiance or luminance of the area.
	www.tfhrc.gov /safety/hsis/pubs/04148/introduction.htm (1334 words)

	Facts of Light – Part 3: Making Sense of Light Measures by Sanjay Joshi - Reefkeeping.com (Site not responding. Last check: 2007-11-01)
		Radiant Intensity is the radiant flux per unit solid angle and is measured in watts/steradian.
		The radiant intensity is independent of the distance because it measures only the amount of radiant flux contained in the cone with an angle at the apex equal to one steradian.
		Irradiance, also known as radiant flux density, is the radiant flux per unit area at a point on the surface.
	www.reefkeeping.com /issues/2006-04/sj/index.php (1944 words)

	>ERBE Earth Radiant Fluxes and Albedo for Month Nonscanner (S-10N) Data Set Document (Site not responding. Last check: 2007-11-01)
		In the inversion processing stage, the spacecraft altitude radiances are inverted or reduced to radiant fluxes at the TOA by both a numerical filter technique and a shape factor technique.
		The ratio of shortwave radiant flux to the integrated solar incidence, where zero (0.0) represents total absorption, and one (1.0) represents total reflectance.
		The radiant flux per unit solid angle per unit of projected area of the source; usual unit is the watt per squa
	charm.larc.nasa.gov /GUIDE/dataset_documents/erbe_s10n.html (9596 words)

	Bright View Electronics Co., Ltd.
		Radiometry and radiometric units such as radiant flux relate to properties associated with the energy of electromagnetic radiation.
		Photometry and photometric units such as luminous flux relate to the properties of light with reference to the sensitivity of the human eye.
		Luminous efficacy of a source is the ratio of output luminous flux (lm) to input electrical power (W).
	www.bvled.com.tw /08_faq.htm (479 words)

	Notes on LEDs
		If the radiant flux of a source is radiated uniformly in all directions, the radiant intensity will be simply the total radiant flux divided by 12.57 (4π) steradians, the solid angle of a complete sphere.
		Radiant power of a wavelength of 555 nm is multiplied by a factor of 1, but light of higher and lower wavelengths are multiplied by lower factors, until infrared and ultraviolet wavelengths are reached, when the radiant power is multiplied by zero.
		IR and UV LEDs are measured in watts for radiant flux and watts/steradian for radiant intensity.
	www.gizmology.net /LEDs.htm (3731 words)

	oe magazine - test talk (Site not responding. Last check: 2007-11-01)
		The absolute spectral power responsivity is the ratio of the output of a photodetector (in amperes or volts) to the spectral radiant flux (in watts) input to the photodetector.
		is the output flux from the monochromator and
		As the name suggests, in the substitution method we measure spectral radiant flux for the standard detector and for the detector under test and use equation (1) to calculate the result.
	oemagazine.com /FromTheMagazine/nov01/testtalk.html (597 words)

	Photonics Dictionary, Definitions, Abbreviations, Illustrations, Terms Listed by Letter R - (Items 1 thru 40) - The ... (Site not responding. Last check: 2007-11-01)
		Excerpt: Ratio of the radiance of the specimen to that of a perfect r...
		Excerpt: The ratio of the radiant flux emitted by a source to the pow...
		Excerpt: Infrared radiation emitted from a source that is not heated...
	www.photonics.com /dictionary/listbyletter/XQ/ASP/url.listbyletter/letter.r/listed.term/pu./QX/listbyletter.htm (515 words)

	Outgoing Longwave Radiant Flux from the Earth Radiation Budget Experiment
		The geophysical data from which the outgoing longwave radiation data set is derived was originally produced by the ERBE Science Team, led by Dr. Bruce Barkstrom (Barkstrom et al., 1989) in the Atmospheric Sciences Division of NASA's Langley Research Center.
		The incoming radiation from the sun is either reflected by the Earth's atmosphere and surface, or is absorbed.
		To study the diurnal cycles of the radiation budget at any geographic location, more than one satellite is needed to obtain the necessary sampling rate (Barkstrom and Smith, 1986).
	disc.gsfc.nasa.gov /interdisc/readmes/erbe.shtml (2789 words)

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