What produces the photons in light bulb filament?

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SUMMARY

The discussion centers on the production of photons in incandescent light bulb filaments, specifically through thermionic emission. Electrons emitted from the filament collide with filament atoms, causing vibrations that heat the atoms and elevate bounded electrons to higher energy levels. When these electrons return to their original states, they release energy as photons. Incandescent bulbs emit primarily infrared light, transitioning to visible light at temperatures around 2,200°C. The continuous spectrum of radiation emitted is attributed to the band structure of solid materials, contrasting with the discrete emission lines seen in gas lamps.

PREREQUISITES
  • Understanding of thermionic emission in incandescent bulbs
  • Knowledge of electron energy levels in solid materials
  • Familiarity with black body radiation concepts
  • Basic principles of emission spectra in gas discharge lamps
NEXT STEPS
  • Research the principles of thermionic emission in detail
  • Explore the concept of black body radiation and its applications
  • Study the differences between solid-state and gas discharge lamp emission spectra
  • Investigate the impact of temperature on the emission of visible light in incandescent bulbs
USEFUL FOR

Physicists, electrical engineers, lighting designers, and anyone interested in the principles of light production in incandescent and gas discharge lamps.

Barry Bonobo
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What produces the photons in light bulb filament? I know that electrons are emmitted by thermionic emmission from the filament . . . do they then fall back into the filament and emit EM radiation as they de-accellerate into the filament?
 
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Nice thanks. Here's the except with the explanation:

"As these free electron move through the filament at high speeds they are constantly bumping into the atoms that make up the filament, the impact energy vibrating and heating these atoms. Bounded electrons in the atoms of the filament are temporarily boosted to a higher energy level. When the electron returns to its original energy level they release the extra energy in the form of photons. Metal atoms release primarily infrared light photons which happen to be invisible to the human eye, but if heated to a high enough temperature (around 2,200 C) will emit the visible light seen from a bulb. "

I wonder now though why it's a nice continuum of EM radiation, rather than discrete lines of radiation we usually see. . .
 
I might be wrong but...

In a solid I believe the energy levels form bands rather than discrete levels. So you get a near continuous spectrum of radiation (Black body)

In a gas lamp the energy levels are discrete so you get characteristic emission lines.
 
http://www.asdi.com/getmedia/05be99...CTRAL-SIGNATURES-OF-NIGHTTIME-LIGHTS.pdf.aspx

Conclusion
We found substantial variation in the emission spectra of lighting types. Lamps that produce
light through heat (incandescent, quartz halogens, and fuel lamps) emit primarily like blackbodies, with
peak emission in the near infrared and emissions higher in the red than green and blue. Fluorescent,
metal halide, high pressure and low pressure sodium lamps are gas discharge lamps, which emit
different series of narrow emission lines. The identity of the gas discharge lamps can be discerned
based on the wavelength positions of the emission lines...

continues
 

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