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Topic: Blackbody spectrum


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  Phys111_ch_3
Blackbody radiation experiment was the first to generate a wide spread interest among physicists to reformulate the theory of light.
In the experiment, the flbody is kept at a constant temperature and, the power of electromagnetic radiation coming out of the flbody is measured as a function of wavelength.
BLACKBODY RADIATION: The continuous spectrum emitted by a hot solid is often approximated as the spectrum of a hot ideally flbody.
www2.potsdam.edu /islamma/phys111_ch_03.htm   (1128 words)

  
 Electromagnetic spectrum - Wikipedia, the free encyclopedia
The electromagnetic spectrum, shown in the table, extends from frequencies used in the electric power grid (at the long-wavelength end) to gamma radiation (at the short-wavelength end), covering wavelengths from thousands of kilometres down to fractions of the size of an atom.
If the spectrum is composed of background light, parts of which the object transmits and parts of which it absorbs, an absorption spectrum occurs.
A rainbow shows the optical (visible) part of the electromagnetic spectrum; infrared (if you could see it) would be located just beyond the red side of the rainbow with ultraviolet appearing just beyond the violet end.
en.wikipedia.org /wiki/Electromagnetic_spectrum   (1476 words)

  
 Blackbody Information - TextSheet.com   (Site not responding. Last check: 2007-11-06)
In physics a flbody is an object that absorbs all light that falls onto it (and thus reflects none).
The spectrum (amount of light emitted at each wavelength) of a flbody is very characteristic, and depends entirely on its temperature.
The spectrum of a flbody was first derived by Max Planck, who had to assume that electromagnetic radiation could propagate only on discrete packets, or quanta.
no-requests.sferahost.com /encyclopedia/b/bl/blackbody.html   (335 words)

  
 Blackbody Radiation - Cancer Therapy   (Site not responding. Last check: 2007-11-06)
main graph is the intensity of the radiation of the flbody as a function of the wavelength, l...
The equation for flbody radiation (the Planck equation) is...
The wavelength of the peak of the flbody radiation curve decreases in a linear fashion as the temperature...
cancertherapy.ftherapy.com /index.php?k=blackbody-radiation   (921 words)

  
 Glossary of Terms for UNH ESPG
Blackbody spectrum: The continuous spectrum emitted by a flbody; the flux at each wavelength is given by Planck's law.
Cosmic flbody microwave radiation: Radiation with a flbody spectrum at a temperature of about 2.7 K permeating the universe; believed to be the remains of the primeval fireball in which the Universe was created.
Spectrum: The array of colors or wavelengths obtained when light is dispersed, as by a prism; the amount of energy given off by an object at every different wavelength.
www-ssg.sr.unh.edu /tof/Outreach/glossary.html   (3186 words)

  
 lesson1
We call it a flbody because, for optical radiation, a fl object is the closest approximation to a perfect absorber.
A flbody spectrum is an idealization -- very few objects radiate a perfect flbody spectrum -- but many objects radiate a continuous spectrum that is a fairly good approximation to a flbody spectrum.
If stars and other objects in the universe radiated exactly as flbodies, we would only be able to determine their temperatures and surface areas by remote sensing.
super.colorado.edu /~astr1020/L1S3.html   (852 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".
spectrum of wavelengths and, based on careful measurements and quantum theory, Max Planck produced an equation to model the observed flbody radiation curve.
At around 500°C there is enough emitted energy in the visible spectrum to be seen as a red glow, changing to yellow as the temperature increases.
www.electro-optical.com /bb_rad/bb_rad.htm   (439 words)

  
 Cosmic Microwave Background Radiation Blackbody - Cancer Therapy   (Site not responding. Last check: 2007-11-06)
spectrum of the cosmic microwave background radiation with that from a precise flbody...
The Cosmic Microwave Background is flbody radiation at a temperature of 2.725 Kelvin.
COBE established the precise flbody character of the radiation and measured the temperature as 2.726 K, measured the...
cancertherapy.ftherapy.com /index.php?k=cosmic-microwave-background-radiation-blackbody   (1216 words)

  
 Appendix A   (Site not responding. Last check: 2007-11-06)
Rather than show the spectrum directly in terms of frequency f, it is often desirable to use the variable (1/l) as a normalized frequency, which is proportional to f.
The variable P’ (for the 1/l spectrum) is zero at zero frequency or infinite wavelength, whereas the variable P (for the l spectrum) is zero for zero wavelength or infinite frequency.
An ideal flbody radiator operates under conditions of thermal equilibrium, and under this condition the photons are packed as closely as is physically possible.
www.olduniverse.com /appendix_a.htm   (1384 words)

  
 notes1
The peak of a flbody spectrum is at a photon energy which is proportional to the temperature of the emitting body.
Thus the whole spectrum of a source moving toward you is shifted toward the high energy end, and the spectrum of a source moving away from you is shifted toward the low energy end.
The continuum spectrum is produced in the lower denser photosphere, and the absorption lines are produced in the upper, less dense photosphere.
www.gpc.edu /~fbuls/ast102/notes/notes1.htm   (7419 words)

  
 Star Light, Star Bright -- Science Background
We name regions of the spectrum rather arbitrarily, but the names give us a general sense of the energy; for example, ultraviolet light has shorter wavelengths than radio light.
For any temperature, the flbody curve shows how much energy (intensity) is radiated at each wavelength, and the wavelength where the intensity peaks determines the color of that the object.
Blackbody curves, for objects of all temperatures, have a similar shape, as shown in the graphsbelow.
amazing-space.stsci.edu /resources/explorations/light/star-light-science.html   (1591 words)

  
 ATOMS & LIGHT
A cool, transparent gas, in front of a source of a continuous spectrum, produces an absorption spectrum.
An example is the familiar rainbow spectrum of visible light obtained by passing white light through a prism.
A flbody is an object that absorbs all the light that hits it.
www.geocities.com /phsastronomy2003/atoms   (891 words)

  
 Blackbody Spectrum   (Site not responding. Last check: 2007-11-06)
It is indicated by the red column in the thermometer on the right side, and you can change it by clicking and/or dragging on it with you mouse.
The main graph is the intensity of the radiation of the flbody as a function of the wavelength,
For flbody radiation, this is only a function of the temperature.
lectureonline.cl.msu.edu /~mmp/applist/blackbody/black.htm   (164 words)

  
 Radio Emission
A flbody is a hypothetical object that completely absorbs all of the radiation that hits it, and reflects nothing.
The image at left shows flbody spectra for objects at three different temperatures: 5000 K, 4000 K, and 3000 K. It is apparent from the image that objects at lower temperatures emit more radiation at longer wavelengths.
The flbody nature of the microwave background spectrum matches the predictions of the Big Bang theory extremely accurately, thus confirming the theory that the microwave background radiation was created in the Big Bang explosion.
www.nrao.edu /whatisra/mechanisms.shtml   (2526 words)

  
 [No title]
June 26 Telescopes and the Nature of Light Comins & Kaufmann: Chapters 3 & 4 ============================================ Spectra -------- Blackbody Radiation Blackbody = object that absorbs all of the light that hits it; no incident light is reflected or scattered off of its surface e.g.
Blackbody will emit different color light Introduce flbody curve: intensity vs. wavelength Let's quantify this with physical laws 1.
A cool gas in front of a hot opaque object produces an absorption line spectrum-- a series of dark spectral lines are seen on a rainbow-colored background different colored lines will be blanked out depending on which chemical elements are present in the gas e.g.
www.ucolick.org /~anne/teaching/lec04.txt   (730 words)

  
 Lecture 4: Blackbody Radiation
Blackbody spectrum only depends on the surface temperature of the object.
Shape of the flbody curve is the same for all temperatures.
The red curve represents the spectrum of a perfect flbody with surface temperature T=5800 K. The Sun's spectrum can be approximated by a flbody spectrum.
www.phys.ualberta.ca /~morsink/astro122/lectures/lect4/lecture4.html   (519 words)

  
 ASTR 1110 Lectures Spring 1999
Spectrum refers to the amount of light observed as a function of wavelength, where longer wavelengths are "redder" and shorter wavelengths are "bluer".
The mathematical description of a flbody spectrum is called the Planck function and depends on some constants (like the speed of light) and the temperature of the object.
This is parameterized by the albedo, A, of the object, where A=0 is a perfectly fl and absorbing surface, and A=1 is a perfectly reflective surface.
lasp.colorado.edu /~colwell/astr3750-f00/dec5notes.html   (620 words)

  
 PHY103 Stars and Galaxies: The Solar Spectrum   (Site not responding. Last check: 2007-11-06)
As the Sun is not an exact flbody, the temperatures obtained from these equations are only approximate: they will not be equal to each other, nor to the "physical" temperature.
The effective temperature of the Sun is about 5770 K, and the corresponding flbody curve is shown as a dashed line in the diagram.
The most convenient observational method to derive the temperature from the continuum spectrum is to measure the ratio of fluxes (difference of magnitudes, i.e.
www.shef.ac.uk /physics/teaching/phy103/solspec.html   (436 words)

  
 Project LITE Spectrum Explorer | User's Guide
The Spectrum Explorer (SPEX) is a powerful new tool which allows users to simultaneously plot and compare multiple spectra, including flbody spectra of any temperature, astronomical data files, and hand-drawn plots.
This information includes the temperature of the flbody, the location of the Wien peak, the Stefan-Boltzmann flux, and the percentage of radiation emitted in the infrared (IR), visible, and ultraviolet (UV) portions of the electromagnetic spectrum.
When comparing two spectra such as a flbody spectrum and a stellar data file, you may wish to adjust the height of one of the curves to achieve a better fit.
lite.bu.edu /spex/build_0041/spex_ug.html   (1367 words)

  
 Blackbody Radiation   (Site not responding. Last check: 2007-11-06)
It's spectrum isn't as smooth as the "ideal" and is pitted and bumpy due to real-world conditions (including, but not limited to, absorption of the radiation en route to the earth).
The first is to vary the actual temperature of the object, by moving the slider back and forth (from near zero degrees to a maximum of 10,000 degrees).
A simulation of the visible spectrum is displayed under the curve, corresponding to 400 (blue), 560 (green), and 700 (red) values.
webphysics.davidson.edu /alumni/MiLee/java/bb_mjl.htm   (221 words)

  
 Thermal Radiation   (Site not responding. Last check: 2007-11-06)
This is a short explanation of what flbody radiation is, and how thick the gas mass has to be for the radiation field to look like flbody radiation.
The flbody spectrum is zero for zero energy, rises to some maximum, and then falls off exponentially at high energy.
The energy at which the spectrum is maximum is just the Boltzmann constant times the temperature of the gas with which the photons are in LTE, which is why the temperature determines the shape of the spectrum by itself.
www.ipp.mpg.de /~bds/astro/thermal-radiation.html   (530 words)

  
 SPI / library / blackbody radiators
Remember that all objects are flbody radiators, and that the spectrum of an object's flbody radiation is determined by the object's temperature, and by its emissivity.
Most of the heat transferred into the room, and to the people in it, is transferred as flbody radiation, and not as a result of the radiator heating the air that is in contact with it, although that certainly does happen as well.
As flbody radiators, they emit considerable amounts of energy (roughly 100 W for an average adult at rest) in the infrared region of the spectrum.
www.x20.org /library/thermal/blackbody.htm   (2936 words)

  
 Abstracts Series 2 Vol. 2B
Experiments performed with Tesla coils tuned to the modal spectrum of solar ambipolar radiation (OR subspectrum), show indirect generation of LFOT photons, and the tuning of such coils to generate ambipolar radiation in the DOR subspectrum is shown to generate HFOT photons.
It is proposed that all flbody radiation spectra result from aether (massfree) energy spectra formed within an aether electric (ambipolar) continuum of massfree energy, and a formal aetherometric model is introduced to permit correlation between the two energy spectra, aether and photonic, employing solar radiations as an example.
Lastly, a prediction of radio CBR flbodies issued from cosmological protons and other hadrons in resonance with the identified spectrum of cosmological ORgone energy is presented, together with a model of how it might account for observed anisotropies of the microwave CBR spectrum.
www.aetherometry.com /abs-AS2v2B.html   (2550 words)

  
 Blackbody Radiation   (Site not responding. Last check: 2007-11-06)
One of the observations that was unexplained at the end of the 19th century was the spectrum of light emitted by hot objects.
The spectrum of light emitted by an ideal hot dense object, called a flbody, is shown in figure 1.
Note that the peak of the flbody spectrum for 6000 K, the surface temperature of the sun, falls at the blue end of the visible range.
venables.asu.edu /quant/DavidS   (554 words)

  
 Lecture 3 - Thermal Radiation, Brightness & Intensity (1/19/99)
The spectrum of this "thermal" radiation depends on the thermal distribution of velocities and thus kinetic energies of the atoms in the material.
The thermal spectrum of photons is continuous, a smooth function of wavelength, in contrast to the spiky line emission at the discrete energy levels of atoms.
The thermal spectrum is a maximum (brightest) at a characteristic wavelength L_max inversely proportional to the temperature:
www.aoc.nrao.edu /~smyers/courses/astro12/L3.html   (1168 words)

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