1. The problem statement, all variables and given/known data An electron (mass m) is contained in a cubical box of widths Lx = Ly = Lz. (a) How many different frequencies of light could the electron emit or absorb if it makes a transition between a pair of the lowest five energy levels? What multiple of h2/8mL2 gives the (b) lowest, (c) second lowest, (d) third lowest, (e) highest, (f) second highest, and (g) third highest frequency? 2. Relevant equations h/2m E0=π2ℏ2/2mL2 3. The attempt at a solution First we have E(111)? Which is E0 * 3 Then we have E(112?) Which is E0 * 6? How should I continue? I do now understand how I can decide how many different frequencies of light there could be. I know that (Lx^ 2 + Ly^ 2 + Lz^2) is important But how to deal with this??