# Wavenumber, transitions

1. Sep 6, 2010

### rayman123

1. The problem statement, all variables and given/known data
Calculate a diameter of an H-atom with n=732. Calculate also the value of the wavenumber corresponding to the transition from n=732 to n=731

2. Relevant equations

$$E_{trans}= \frac{-E_{h}}{(732)^2}-\frac{-E_{h}}{(731)^2}}$$

3. The attempt at a solution

$$E_{trans}= \frac{-13.6}{(732)^2}-\frac{-13.6}{(731)^2}}=6.95\cdot10^{-5} eV$$

$$E=\frac{hc}{\lambda}\Rightarrow \lambda=\frac{hc}{E}=\frac{4.135\cdot10^{-15}\cdot 3\cdot10^8}{6.95\cdot10^{-5}}=0.0178 m$$
1. The problem statement, all variables and given/known data

now going back to the wavenumber, i was not sure which formula i should use....
$$k=\frac{2\pi}{\lambda} or \nu=\frac{1}{\lambda}$$
I have chosen the second one and i got
$$\nu=\frac{1}{0.0178}=56.18 m^{-1}$$
1. The problem statement, all variables and given/known data

Is that a relevant result?

3. The attempt at a solution

the diameter will be=
$$d_{n}=2\cdot r_{0}\cdot n^2= 2\cdot (732)^2\cdot 5.291\cdot10^{-5} = 5.67\cdot10^{-5} m$$

Last edited: Sep 6, 2010
2. Sep 6, 2010

Seems OK :)