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Homework Help: Gas density problem

  1. Feb 20, 2006 #1
    If the exospheric temperature is 1500 K and the hydrogen atom and helium atom densities at 500 km are 1x10^4 cm-3 and 1x10^6 cm-3 respectively, determine at what height the hydrogen atom and helium atom densities will become equal. [Hint: The answer is greater than 3000 km and remember that the acceleration due to gravity g decreases with height]

    wel the densities of the gases in the atmosphere is given by
    [tex] n(z) = n_{0} \exp(\frac{-z}{H}) [/tex]
    where H is the scale height [tex] H = \frac{RT}{Mg(z)}[/tex]

    the densities of H are 10^10 m-1 and He 10^12 m-1
    when the densities are equal
    [tex] 10^{10} \exp\left(\frac{-zg(z)}{1.2 * 10^7}\right) = 10^{12} \exp\left(\frac{-zg(z)}{3.1*10^6}\right) [/tex]
    where [tex] g = \frac{GM}{z^2} [/tex]

    is the setup good so far? Thank you for all your help!
     
  2. jcsd
  3. Feb 23, 2006 #2
    bump !

    can anyone help?

    i jsut wanna know if the setup is correct or not!
     
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