How incandescent light bulbs create light

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Discussion Overview

The discussion focuses on the mechanisms by which incandescent light bulbs produce light, exploring atomic-level explanations and the nature of the emitted light. Participants examine whether the light is primarily due to electron transitions or thermal radiation, and consider the implications of different types of spectra produced.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes that the light from a tungsten incandescent bulb may result from electrons gaining energy from a high voltage current and emitting photons as they return to ground state.
  • Another participant suggests that the light is produced through incandescence due to high temperatures, which causes the tungsten to emit visible light rather than just infrared.
  • Some participants question whether both mechanisms contribute to light production, indicating confusion over the nature of the emitted spectrum.
  • A participant challenges the idea of a line spectrum being present in incandescent light, suggesting a comparison with CFLs to illustrate differences in emitted spectra.
  • It is noted that while both mechanisms might contribute, incandescence is considered to be the dominant process in light production within a bulb.

Areas of Agreement / Disagreement

Participants express differing views on whether the light production is solely due to incandescence, solely due to electron transitions, or a combination of both. The discussion remains unresolved with multiple competing perspectives on the mechanisms involved.

Contextual Notes

Participants reference the collective behavior of atoms in solids and its impact on light emission, but the implications of this concept are not fully explored or agreed upon.

Yaus Man
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I'm looking at how incandescent light bulbs create light in a more in depth manner, not just "filament gets hot and it glows". I want to know the actual science in an atomic level.

I have been researching through books and the internet, and have yet to come to a conclusion whether the light from a tungsten incandescent light bulb comes from:

a) The current passing through with a high voltage gives energy to electrons to jump to a higher energy level, and drops back down to ground state, spontaneously emitting photons (visible light).

or

b) Incandescence, simply due to the high temperature, which meant that the tungsten radiates some visible light instead of only infrared.

or

c) Both?

I am really confused by all these information, some saying it's (a), some say it's (b).
 
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Yaus Man said:
b) Incandescence, simply due to the high temperature,
A continuous spectrum;
Yaus Man said:
higher energy level, and drops back down to ground state
A line spectrum; which makes sense?
 
Bystander said:
A continuous spectrum;

A line spectrum; which makes sense?

So are you saying it's both? Both are responsible for producing light?

Thanks a lot I really appreciate your reply.
 
Do you see any hint of a line spectrum from an incandescent lamp? Compare it to a CFL --- look at them alongside one another through beveled glass.
 
Yaus Man said:
So are you saying it's both?
No. He's asking you what you think the spectrum of light looks like.

Consider this quote from the FAQ https://www.physicsforums.com/threads/do-photons-move-slower-in-a-solid-medium.511177/
ZapperZ said:
Do Photons Move Slower in a Solid Medium?
When atoms and molecules form a solid, they start to lose most of their individual identity and form a "collective behavior" with other atoms. It is as the result of this collective behavior that one obtains a metal, insulator, semiconductor, etc. Almost all of the properties of solids that we are familiar with are the results of the collective properties of the solid as a whole, not the properties of the individual atoms.
 
Last edited by a moderator:
Yaus Man said:
So are you saying it's both? Both are responsible for producing light?

Both would be responsible to some degree, but incandescence is overwhelmingly dominant in a light bulb.
 

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