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Homework Help: Value of inifinity?

  1. Dec 19, 2007 #1
    [SOLVED] Value of inifinity?

    Edit: typo in title (infinity); sorry

    1. The problem statement, all variables and given/known data

    What is the shortest wavelength of light emitted by an electron in the Brackett series of spectra lines of the hydrogen atom?

    2. Relevant equations

    1 / (wavelength) = RH ( (1/nu^2) - (1/nl^2) )

    3. The attempt at a solution

    1 / (wavelength) = 1.1 x 10^7 ( (1/4^2) - (1/(infinity???)^2) )

    I am told the correct answer is 1.45 x 10^-6, but I cannot find it on my calculator because I am not sure what to put in the place of infinity.

    Last edited: Dec 19, 2007
  2. jcsd
  3. Dec 19, 2007 #2


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    One over a number infinitely close to infinity is infinitely close to zero. Just put in zero for the second term.
  4. Dec 19, 2007 #3

    Shooting Star

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    The value of 1/x tends to zero as x tends to infinity.So, just put zero in place of 1/n1^2.
  5. Dec 20, 2007 #4

    Shooting Star

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    (Sorry Dick, it seems we were typing at almost the same time.)
  6. Dec 20, 2007 #5
    Thanks guys! :)
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