1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Emission & Energy levels of Hydrogen Problem

  1. Dec 29, 2006 #1
    1. The problem statement, all variables and given/known data

    What values of n are involved in the transition that gives the rise to the emission of a 388-nm photon from hydrogen gas?

    2. Relevant equations

    wavelength = 388nm=3.88x10^-7 m
    R=1.097x10^7 m^-1

    E= hc/ wavelength

    3. The attempt at a solution

    E= hc/ wavelength=(6.63x10^-34)(3.00x10^8)/ (3.88x10^-7) = 5.13x10^-19 J = 3.206 eV

    En = -13.6eV / n^2
    n = - square root of (13.6/En) = -square root of (13.6/3.206) = - square root of 4.24 = -2.06

    n = 2 <- 1st excited state

    the answer is n=8 to n= 2.

    How would I know that it began from n=8 ?? Maybe there's an equation that I missed..
  2. jcsd
  3. Dec 29, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The formula you need to know for this is the rydberg formula.

    [tex]\frac{1}{\lambda}=R_H \left(\frac{1}{(n_1)^2}-\frac{1}{(n_2)^2}\right)[/tex] where, [tex]n_1<n_2[/tex]
    Last edited: Dec 29, 2006
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Emission & Energy levels of Hydrogen Problem