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	Infrared Blackbody Theory
		Although the emitted radiation of a body includes all wavelengths, the region in which the amount of radiation is significant to industrial temperature measurement extends from 0.3µm to about 20µm.
		The thermal energy radiated by an object is expressed in relation to the energy radiated at the same temperature by a perfect radiator, traditionally called a fl body.
		Though the flbody is an ideal, and no perfect flbody exists, specially constructed laboratory sources emit radiation with an efficiency compared to a flbody of 98% or higher.
	www.mikroninfrared.com /products/blackbody/about-blackbody.html (774 words)

	Blackbody Radiation
		"Blackbody radiation" or "cavity radiation" refers to an object or system which absorbs all radiation incident upon it and re-radiates energy which is characteristic of this radiating system only, not dependent upon the type of radiation which is incident upon it.
		The amount of radiation emitted in a given frequency range should be proportional to the number of modes in that range.
		The Planck radiation formula is an example of the distribution of energy according to Bose-Einstein statistics.
	hyperphysics.phy-astr.gsu.edu /hbase/mod6.html (562 words)

	BB Radiation
		Herschel found that the heating effect increased toward the red and continued to increase as he moved the thermometer into the dark portion beyond the red end of the visible light spectrum, He found the maximum heating occurred considerably beyond the red, in the region we now call "infrared".
		A hot object emits radiation in a range of wavelengths of varying intensities.
		radiant exitance and this can be found by integrating the area under the graph.
	www.electro-optical.com /bb_rad/bb_rad.htm (439 words)

	Radiation Laws
		Generally, flbody conditions apply when the radiator has very weak interaction with the surrounding environment and can be considered to be in a state of equilibrium.
		The primary law governing flbody radiation is the Planck Radiation Law, which governs the intensity of radiation emitted by unit surface area into a fixed direction (solid angle) from the flbody as a function of wavelength for a fixed temperature.
		The behavior of flbody radiation is described by the Planck Law, but we can derive from the Planck Law two other radiation laws that are very useful.
	csep10.phys.utk.edu /astr162/lect/light/radiation.html (530 words)

	Blackbody Radiation
		Blackbodies derive their name from the fact that, if they do not emit radiation in the visible range, they appear fl due to the complete absorption of all wavelengths.
		An additional important parameter of a flbody source is the wavelength where the spectral irradiance is the highest, or, in other words the wavelength where most of the power is emitted.
		For example, near room temperature, a flbody emitter (such as a human body or light bulb which is turned off) will emit low power radiation at wavelengths predominantly greater than 1µm, well outside the visual range of human observation.
	www.udel.edu /igert/pvcdrom/SUNLIGHT/BLAKBODY.HTM (479 words)

	Blackbody radiation
		The theory that radiation causes the dissociation of a molecule as it gains energy from light and starts to break apart was proposed as early as 1919 by Jean Baptiste Perrin, a French Nobel laureate.
		He said that the radiation which a molecule must absorb in order to produce the internal energy to cause it to fragment fell within the ultraviolet light range, and there was not enough of such light to produce observed reactions.
		The radiation theory was ultimately rejected because scientists did not have the instruments to create collision-free, low-pressure conditions under which radiation-induced unimolecular dissociation could be observed.
	www.case.edu /pubs/cnews/1998/1-29/science.htm (683 words)

	Blackbody Radiation
		The flbody radiation is seen as a remnant of the transparency point at which the expanding universe dropped below about 3000K so that radiation could escape.
		A uniform background radiation in the microwave region of the spectrum is observed in all directions in the sky.
		The discovery of the 3K microwave background radiation was one of the crucial steps leading to the calculation of the standard "Big Bang" model of cosmology, its role being that of providing estimates of relative populations of particles and photons.
	hyperphysics.phy-astr.gsu.edu /hbase/bkg3k.html (947 words)

	Blackbody Radiation - Slackerpedia Galactica (Site not responding. Last check: 2007-10-13)
		A mythical spectrum by a mythical beast that eats energy and radiates heat.
		A true flbody (a) gets more luminous, and (b) has a spectrum that peaks at shorter and shorter wavelengths as it gets hotter.
		Stars are really not flbodies (because they have emission and absorption lines in their spectra), but they play them on television.
	www.slackerastronomy.org /slackerpedia/index.php/Blackbody_Radiation (211 words)

	Lab 2: Thermal Blackbody Radiation (Site not responding. Last check: 2007-10-13)
		The amount of light per square centimeter that a flbody emits or absorbs at a given wavelength is determined only by the temperature of the flbody.
		This is because the sensor itself radiates infrared light, and the signal generated by the sensor is actually the difference between the incoming and the outgoing IR flux.
		Assuming that the sensor stays at the same distance from the IR source, the proportionality constant between radiation flux and millivolts is the same in both cases.
	geosci.uchicago.edu /~archer/PS134/LabManual/lab.thermal.html (1494 words)

	Foundation of Quantum Theory (Site not responding. Last check: 2007-10-13)
		Thus radiation entering the cavity through the orifice is incident on its flened inner surface and is partly absorbed and partly reflected.
		Planck's formula for the energy distribution of flbody radiation agrees well with the experimental results, both for the long wavelengths and the short wavelengths of the energy spectrum.
		A graphite target was bombarded with monochromatic x-rays and the wavelength of the scattered radiation was measured with a rotating crystal spectrometer.
	physics.berea.edu /~king/Teaching/ModPhys/QM/QM1.htm (2080 words)

	Blackbody Radiation
		One such exception was that associated with flbody radiation, which is the characteristic radiation that a body emits when heated.
		It was known that this radiation changes in nature as the temperature changes, and experiments on ``flbodies'' (perfect absorbers and emitters) show the following typical curves of the intensity of the radiation (energy emitted per unit time per unit area) vs. the wavelength at a fixed temperature T, as in Fig.
		With this photon picture, Planck was able to successfully explain the flbody radiation curves, both at long and at short wavelengths.
	theory.uwinnipeg.ca /physics/quant/node2.html (301 words)

	Blackbody Radiation (Site not responding. Last check: 2007-10-13)
		This radiation which comes from heat is called thermal radiation or flbody radiation.
		It is sometimes called flbody radiation because it is typical of a perfectly absorbing surface (an object which absorbs all of the light which hits it and does not reflect any).
		Blackbody radiation dominates the spectrum of almost all stars.
	spider.ipac.caltech.edu /staff/lmh/Blackbody/blackbody.html (484 words)

	Black Body Radiation
		It was known from Maxwell's equations that this radiation traveled at the speed of light and from this it was realized that light itself, and the closely related infrared heat radiation, were actually electromagnetic waves.
		Radiation impinging on the hole from outside enters the box and is absorbed as it is scattered around inside, so only a tiny fraction is re-emitted.
		A beam of radiation from the hole in the oven is passed through a diffraction grating and projected on to a screen, where it is separated out by wavelength (or equivalently frequency).
	galileo.phys.virginia.edu /classes/252/black_body_radiation.html (3762 words)

	IMSA Astrophysics
		A flbody is a theoretical object which is a perfect absorber and emitter of radiation.
		Nothing is actually a perfect flbody, including stars, but the concept is still a very valid one and is the foundation for spectral analysis.
		The radiation given off by a flbody occurs in a wide range or "spectrum" of wavelengths and, based on careful measurements and quantum theory, Max Planck produced an equation to model the observed flbody radiation curve.
	staff.imsa.edu /science/astro/blackbody (1176 words)

	Blackbody Radiation
		The furnace is in equilibrium as when it absorbs some radiation it emits some to make up for this and eventually a small amount of this emitted radiation may escape to compensate for the radiation that entered through the hole.
		Most approximate flbodies are solids but stars are an exception because the gas particles in them are so dense they are capable of absorbing the majority of the radiant energy.
		This meant that radiation was being thought of as a "packet of energy" but also as a wave because it had a frequency.
	www.egglescliffe.org.uk /physics/astronomy/blackbody/bbody.html (1885 words)

	Blackbody Radiation
		Blackbody radiation is a common phenomenon that probably is familiar to you.
		When you see stars of different colors, when you observe an electric heating coil on a stove turn red, or when you observe a lightbulb, you are observing flbody radiation.
		A flbody is a device that converts heat into radiant energy.
	www.tau.ac.il /~phchlab/experiments/iodine/blackbody_radiation.htm (211 words)

	Radiation Laws
		Although internally, stars do not satisfy perfectly the conditions to be flbody radiators, the surface layers from which we see emission can be approximated as a flbody radiator.
		The primary law governing flbody radiation is the Planck Radiation Law, which governs the intensity of radiation emitted by unit surface area into a fixed direction from the flbody as a function of wavelength for a fixed temperature.
		All heated objects emit a characteristic spectrum of electromagnetic radiation, and this spectrum is concentrated in higher wavelengths for cooler bodies.
	www.pas.rochester.edu /~blackman/ast104/radiation.html (816 words)

	Blackbody
		Radiation coming in will impinge on the material's electrons, some will be reflected, some absorbed.
		C or 310 K. We therefore emit radiation with the peak in the infrared at 9.3 μm.
		Further, the interior radiation must be in an equilibrium state - no light can enter, none can escape so the emissions must balance the absorptions, and the light must be as bright as is possible for the temperature of the room.
	www.launc.tased.edu.au /online/sciences/physics/blackbody1.html (1162 words)

	Wien's Law and Blackbody Radiation
		A flbody is a theoretical object that is a perfect emitter and absorber of radiation.
		The foundation of flbody radiation lies in the idea that radiation is released from flbodies in the form of "quanta" or little discrete packets of light called photons.
		He and his contemporaries were the ones that discovered that all bodies constantly emit radiation and that the spectrum of this radiation does not depend on the composition of the object.
	feps.as.arizona.edu /outreach/bbwein.html (1045 words)

	Blackbody radiation
		"Blackbody" means that the system is in thermodynamic equilibrium so that there is detailed balance balance between emitted and absorbed radiation.
		It was coined on the basis of the property of absorbing all the radiation that impinges on an object but that description leaves out the second equally important quality, namely that it also emits exactly as much radiation as it absorbs.
		The key property of a "flbody" is that such an object is thermodynamic equilibrium.
	www.physicsforums.com /showthread.php?p=405526 (275 words)

	Blackbody Radiation (Site not responding. Last check: 2007-10-13)
		This shows that cooler objects radiate most of their light towards the red end of the spectrum.
		Hotter stars have more blue in their spectrum while cooler stars radiate more in the red end.
		Actually most stars are cool red stars which radiate much of their energy in the infrared.
	spider.ipac.caltech.edu /staff/lmh/Blackbody/starcolors.html (389 words)

	Blackbody Radiation (Site not responding. Last check: 2007-10-13)
		Remnant heat from the "big bang," first detected in 1965, is in the form of microwave radiation because the universe has cooled considerably since its birth.
		But the universe acts as a perfect emitter and absorber of radiation, and for this reason it is called a "flbody" as all objects are which emit and absorb perfectly.
		Our Sun is almost a flbody, so we'll use it as an example of what to expect from the much cooler universe.
	physics.scsu.edu /~dms/cosmology/blackBody.html (138 words)

	Blackbody Radiation
		Electromagnetic radiation can be described in terms of wavelength (lsmbda) or frequency (f = c/lambda), ranging from long-wavelength radio waves (lambda many km) to gamma rays (lambda as short as 1 fm = 10^-15m).
		is also equal to the absorptivity of the surface (the fraction of electromagnetic radiation of a given wavelength which would be absorbed if the surface were illuminated by an external source) a fl body absorbs all radiation, even that in the visible region of the spectrum, and therefore appears fl.
		But for mathematical convenience, Planck assumed the radiated energy to occur in discrete (quantised) amounts (rather than a continuous range of values) and found that he was then able to derive his radiation formula.
	laser.phys.ualberta.ca /~egerton/bbradn.htm (948 words)

	Black body - Wikipedia, the free encyclopedia
		It is the most perfect flbody emission known and corresponds to a temperature of 2.725 kelvins with an emission peak of 160.4 GHz.
		No radiation passes through it and none is reflected, yet in classical physics, it can theoretically radiate any possible wavelength of energy.
		The radiance or observed intensity is not a function of direction.
	en.wikipedia.org /wiki/Blackbody_radiation (1967 words)

	Blackbody Radiation (Site not responding. Last check: 2007-10-13)
		Even though by definition, they are not perfect flbodies, for the sake of understanding and simplicity we can apply the characteristics of flbodies to them.
		Secondly, we know that all flbodies do not radiate energy at the same rate, certainly shown by the sun's power compared to that of the earth.
		Stefan-Boltzmann's law states that the rate that a body emits radiation (per unit area) is directly proportional to the body's absolute temperature to the fourth power.
	weather.cod.edu /sirvatka/blackbody.html (370 words)

	Electromagnetic Spectrum : Blackbody Radiation (Site not responding. Last check: 2007-10-13)
		A flbody is defined as an object that absorbes all incoming radiation and emmits all energy at full efficiency for all wavelengths.
		The x-axis is wavelength, and the y axis is radiation intensity (B).
		The earth radiation peak corresponds to the infrared portion of the spectrum.
	marine.rutgers.edu /mrs/education/class/josh/black_body.html (345 words)

	Blackbody Sound Radiation
		Since all modes have equal average power, which simply add for the total power, this indicates that the "flbody" pressure noise within the gas, in a narrow frequency band, is proportional to the square of the frequency.
		It seems odd that the flbody spectrum of pressure within the gas is completely different than the spectrum of the force exerted by the pressure, but that's the result.
		To evaluate the mean-square force on the piston within the bandwidth Δf, we use equation (4), reduced by a factor of 4 since two of the indices are zero, multiplied by the number of modes.
	www.silcom.com /~aludwig/Physics/Noise_floor/Blackbody.htm (1687 words)

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