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Question with respect to a Max Planck article

  1. Jan 28, 2015 #1
    This is not a homework problem, this is a question borne out of self-interest.

    I picked up the book "The Dreams that Stuff is Made of" by Stephen Hawking:
    (https://www.amazon.com/Dreams-That-Stuff-Made-Physics/dp/0762434341 )

    and read the first article by Max Planck: "On the Distribution of Energy in the Normal Spectrum."
    (The article can be found here: http://theochem.kuchem.kyoto-u.ac.jp/Ando/planck1901.pdf )

    Just reading this article without understanding the formulas is surely not enough and my question is what all of the symbols mean in (3) of the article: SN = k log W + constant

    S -> the average entropy of a single resonator
    Subscript N -> the set of identical resonators

    Now, log W is supposed to denote the probability of a set system of entropy existing if I understood this part correctly. My specific questions are:

    What purpose does the k serve in front of log W?
    What purpose does the +constant serve?
    Why use log W to denote the probability of a set system of entropy existing?

    If anyone has read this article, or chooses to do so before responding, could you please point me towards some references that might assist me in understanding probability and the rest of the elements in this formula?

    Thank you for your time
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Jan 28, 2015 #2


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    W is the number of "ways" or elementary configurations the system of resonators can be in (i.e., the number of ways the energy quanta can be distributed among all the N rasonators).

    k is Boltzmann's constant. It serves as a constant of proportionality so that the statistical formulation of the entropy and the thermodynamic formulation of the entropy are equivalent.

    As far as useful references go, I think pretty much any upper-level undergraduate text book on statistical mechanics and thermodynamics will cover how to derive the blackbody spectrum. I am particularly partial to Kittel and Kroemer's "Thermal Physics".
  4. Jan 29, 2015 #3
    Thank you very much for your response as I now know where and what to look for in my university library. I checked the reference website and we have this text by Kittel and Kroemer. Thank you once again for the response.
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