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(Redirected from Incandescent)
'Incandescence' is the release of thermal radiation from a body due to its temperature. The distribution of energy emissions across the electromagnetic spectrum is described by Planck's law; at temperatures occurring on Earth, the release of radiation is usually predominantly in the infrared and visible regions of the electromagnetic spectrum. The total power emitted by radiation is given by the Stefan-Boltzmann law.
Incandescence occurs in light bulbs, because the filament resists the flow of electrons. This resistance heats the filament to a temperature where part of the black body radiation falls in the visible spectrum. The majority of radiation, however, is emitted in the invisible infrared and lower frequency spectrums, which is why incandescent light bulbs are very inefficient. The mechanism of the incandescence is as follows: the temperature of the filament causes electrons in it to be excited to an atomic orbital of higher energy; when an electron falls back to the more stable ground state orbital, it releases the energy thus stored, in the form of a photon. The frequency of the emitted photon is determined by the energy difference between the two orbitals. The same process occurs in plasma, of which fire is a well-known example.
Fluorescent lamps do not function by means of incandescence, rather by a combination of thermionic emission and atomic exitation.
★ Incandescent light bulb
★ Black body
★ List of light sources
Molten glassy material glows orange with incandescence in a vitrification experiment.
The incandescent metal embers of the spark used to light this Bunsen burner emit light ranging in color from white to orange to red. This change correlates with their temperature as they cool in the air. Note that the flame itself is not incandescent as its blue color is due to various other atomic and molecular energy transitions.
'Incandescence' is the release of thermal radiation from a body due to its temperature. The distribution of energy emissions across the electromagnetic spectrum is described by Planck's law; at temperatures occurring on Earth, the release of radiation is usually predominantly in the infrared and visible regions of the electromagnetic spectrum. The total power emitted by radiation is given by the Stefan-Boltzmann law.
Incandescence occurs in light bulbs, because the filament resists the flow of electrons. This resistance heats the filament to a temperature where part of the black body radiation falls in the visible spectrum. The majority of radiation, however, is emitted in the invisible infrared and lower frequency spectrums, which is why incandescent light bulbs are very inefficient. The mechanism of the incandescence is as follows: the temperature of the filament causes electrons in it to be excited to an atomic orbital of higher energy; when an electron falls back to the more stable ground state orbital, it releases the energy thus stored, in the form of a photon. The frequency of the emitted photon is determined by the energy difference between the two orbitals. The same process occurs in plasma, of which fire is a well-known example.
Fluorescent lamps do not function by means of incandescence, rather by a combination of thermionic emission and atomic exitation.
| Contents |
| See also |
See also
★ Incandescent light bulb
★ Black body
★ List of light sources
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