1. The problem statement, all variables and given/known data 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. 2. Relevant equations wavelength = (8mc2L2)/(hc(ni2 - nf2) 3. 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.