Light scattering and thermal emission of a body

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Discussion Overview

The discussion revolves around the relationship between the absorption spectrum and thermal emission spectrum of colored bodies, specifically using the example of a green snooker ball. Participants explore concepts from quantum mechanics regarding black body radiation and how color affects emission patterns at a given temperature.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the emission pattern of a green snooker ball at temperature T, suggesting a potential relationship between absorption and thermal emission spectra.
  • Another participant asserts that the emission spectrum of a colored object differs from that of a black body, indicating that a ball reflecting green light would emit less green light when heated.
  • A subsequent post seeks clarification on the shape of the emission spectrum and requests references for further reading.
  • Another participant proposes that two differently composed snooker balls, both painted green, would exhibit the same emission spectrum, questioning the correctness of this assumption.
  • One participant notes that human perception of color is complex and that the proposed spectrum is only one theoretical possibility, suggesting that relevant literature on electrodynamics may provide more insight.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between absorption and emission spectra, with no consensus reached on the correctness of the claims regarding colored bodies and their thermal emission characteristics.

Contextual Notes

Limitations include the complexity of human color perception and the potential variability in emission spectra based on material composition and surface properties, which remain unresolved in the discussion.

Who May Find This Useful

This discussion may be of interest to those studying quantum mechanics, thermodynamics, and the interaction of light with matter, particularly in the context of colored materials and their thermal properties.

DaTario
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hi All,

We know from QM that black bodies at temperature T emits light in a well stabilished patern.
Now what if the body has color? Which is the emission patern of a green snooker ball for example, at temperature T?

When scattering white light we see this ball green because it absorbs everything but this range of frequencies near the green. Is there any universal relationship between the absorption spectrum and this thermal emission spectrum?

Merry Xmas,

Datario
 
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Both spectra are the same. If you heat a ball which reflects most green light, it will emit less green light than a black body.
 
So is the spectrum like the figure attatched? If so, would you have some reference to recomend?

Best wishes,

DaTario
 

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It seems reasonable to think that two snooker balls, one made of iron and the other made of coper, but both painted with green tincture will exhibt the same emission spetrum.

It is correct?

Best wishes

DaTario
 
Our eyes are not spectrometers, there are many ways we can perceive light as green. That spectrum would be a possibility, at least in theory.
Books about electrodynamics and the interaction of light with matter should cover this somewhere.
 

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