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System with entropy k ln 2

  1. Jul 22, 2015 #1

    Philip Wood

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    An old book I have on elementary Statistical Mechanics (Rushbrooke) uses as an especially simple case a system with one energy level. This level is doubly degenerate. The author doesn't give an example of such a system. Can anyone think of one? And would it have entropy [itex]k\ ln 2[/itex]?

    [My thoughts turn to spin 1/2 particles but I'd like comment.]
     
  2. jcsd
  3. Jul 22, 2015 #2
    Real systems tend to have more than two energy levels, but some are approximated as two level systems in certain situations.
     
  4. Jul 22, 2015 #3

    TeethWhitener

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    Yes, a spin 1/2 particle has a doubly degenerate energy level in the absence of a magnetic field.
     
  5. Jul 22, 2015 #4

    Philip Wood

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    DrC and TW. Many thanks for replying.

    TW: would you, then, say that a spin 1/2 particle, viewed as a system, has an entropy of [itex]k\ ln2[/itex] in the absence of a magnetic field?
     
  6. Jul 22, 2015 #5

    TeethWhitener

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    Yes.
     
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