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Why is the conversion from eV to Kelvin so high?

  1. May 15, 2015 #1
    I mean eV are something like 1.6x 10^-19 joules but somehow 7eV corresponds to 81121 K?? At that temperature you should have a lot more energy than 7eV! No?
     
  2. jcsd
  3. May 15, 2015 #2

    ShayanJ

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    Temperature is soemthing which can be defined for only many particle systems, you need to have at least a few hundread particles, if not more!
    Then, the energy equivalent to a particular temperature is interpreted as the average energy of those particles. So when you say 7eV corresponds to 81121 K, it means that in a many particle system with such a temperature, the average energy of particles is 7eV. Some particles have much more energy and some much less.
     
  4. May 15, 2015 #3
    Ah cool, does this have to do with the mean of a Boltzmann distribution? This would mean 7eV being a vibrational energy?
     
  5. May 15, 2015 #4

    ShayanJ

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    Yeah, Boltzmann distribution tells you what fraction of the particles have a particular energy.
    But all the energy doesn't have to be vibrational. It depends on the system. You may have a monatomic gas which can only have translational degrees of freedom. Or you may have something like a water molecule which can rotate around several axis and also has some vibrational degrees of freedom too. Of course the translational degrees of freedom are still present.
     
  6. May 15, 2015 #5
    Ah gotya, but it's still kinetic as opposed to electric which is probably making all the difference. Very cool, thanks man.
     
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