Max Freq & Temp Relation in Wien Displacement Law

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    Displacement Law
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Discussion Overview

The discussion revolves around the relationship between maximum frequency and temperature as described by Wien's displacement law, specifically how to derive this relationship from the known formula involving maximum wavelength and temperature.

Discussion Character

  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant notes that Wien's displacement law relates maximum wavelength and temperature through the equation: wavelength max * Temperature = 2848 micrometer Kelvin.
  • Another participant emphasizes that the shape of the radiation curve for a black body depends on temperature, with the peak position increasing linearly with temperature.
  • A participant seeks a formulaic approach to convert maximum wavelength to maximum frequency, referencing the Planck spectrum and Wien's law.
  • Another participant provides a mathematical substitution, stating that using the relationship between wavelength and frequency (wavelength * frequency = speed of light), one can derive an expression for frequency in terms of temperature.
  • It is mentioned that Wien's law is often quoted in terms of wavelength due to the simplicity of the constant involved, rather than its frequency equivalent.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the derivation process, as some seek clarification on the formula while others provide different perspectives on the relationship between wavelength and frequency.

Contextual Notes

There are unresolved aspects regarding the conversion between wavelength and frequency, and the dependence on specific units (e.g., using speed of light in mm/s) is noted but not fully explored.

yellowgold
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In Wien displacement law we know that

wavelength max * Temperature = 2848 micrometer Kelvin

How we can get the relationship between frequency max and Temperature ?
 
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For a black body the shape of the amount of radiation at each wavelength only depends on the temperature.
The shape of the curve changes with temperature but the position of the peak happens to increase linerarly with temperature.

Edit - sorry did you just mean what's the relationship between wavelength and frequecny?
wavelength * frequency = speed of light (make sure you have the same distance units)
 
Last edited:
Mgb thank you for your answer but I meant that how can I get it by formula. I have Planck spectrum formula SB law and wien law but i don't how how I can covert wavelength max to frequency max and state relationship omega max and temp. ?
 
wavelength * frequency = c (the speed of light)
ie wavelength = c/f
so substiuting in Wein's law
(c/f)* T = 2.848 mm kelvin

or, f = cT/2.848mm ( you will need to use c in mm/s)

Wein's law is only quoted in terms of wavelength because 3mm is such an easy constant to remember instead of it's equivalent in teraHz
 

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