How incandescent light bulbs create light

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SUMMARY

Incandescent light bulbs primarily produce light through incandescence, where the tungsten filament emits visible light due to high temperatures. While there is some contribution from electron transitions, the dominant mechanism is thermal radiation. The light emitted is characterized by a continuous spectrum rather than a line spectrum, distinguishing it from other light sources like CFLs. Understanding the collective behavior of atoms in solids also plays a role in the properties of light emission.

PREREQUISITES
  • Understanding of incandescence and thermal radiation
  • Basic knowledge of atomic structure and electron energy levels
  • Familiarity with light spectra, including continuous and line spectra
  • Concepts of solid-state physics and collective atomic behavior
NEXT STEPS
  • Research the principles of thermal radiation and Planck's law
  • Study the differences between incandescent and CFL light sources
  • Explore the concept of electron transitions in atoms and their role in light emission
  • Investigate solid-state physics and its impact on material properties
USEFUL FOR

Students of physics, electrical engineers, and anyone interested in the science behind light production in incandescent bulbs.

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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