What Is the Length of the Box Based on Photon Emission Wavelengths?

[wompkins]

Homework Statement

Imagine a box of unknown length with the only visible photons emitted have 620nm and 443nm. Identify the transitions and find the length of the box.

Homework Equations

wavelength = (8mc²L²)/(hc(n_i² - n_f²)

The Attempt at a Solution

So I assume that I need to do is make a guess and find the first transition. From there find the ground state and then compare this ground state to the next transition.

From the lecture on this topic though we did not go over any problems like this so I am confused as to find the first transition.

 

[BvU]

Beware the "visible" ! You don't know if there are invisible photons, but you do know that there are no photons with a wavelength in between. Try a few transitions and see what wavelength expressions you get. Perhaps an expression for the difference between two consecutive wavelengths ?

 

[dauto]

Try dividing one wavelength by the other