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Homework Help: Mean Free Path of an Electron in Mercury Vapour

  1. Nov 12, 2009 #1
    1. The problem statement, all variables and given/known data
    Estimate the mean free path of an electron in mercury vapour at a temperature of 160 degrees C, where the vapour pressure is 11.28 mmHg
    It gives the standard atmospheric pressure as 761.84 mmHg.

    2. Relevant equations
    Mean free path= (Boltzmann's constant times temperature)/(sqrt(2)*pi*(d^2)*p)
    where d is the diameter of the molecule and p is the pressure.

    3. The attempt at a solution
    I have: Boltzmann's constant= 1.38x10^-23
    d=302x10^-12 metres
    p=(11.28/761.84)*101325 Pa
    (I think these are all the right units to use)

    So I fill these into the formula and get 9.834x10^-6 m as my value for mean free path. I have nothing to compare this to, so I have no idea whether this is right or way off the mark.
  2. jcsd
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