Okay, so I'll say the question and then say what I have so far:
Take a square box with side .4 nm containing six electrons. Determine the minimum wavelength absorbed (in nm) when an electron is promoted to the first excited state of this system. (Remember, you are treating each state as an orbital)
So I'm not very far but I'm pretty sure I know what equations I'm supposed to use. For a 2D box, the energy is (nx2 + ny2)h2/8mL2. The part that I'm confused about is getting an electron promoted to the first higher state. Does it matter which n I make 1 and which n I make 2 since it's the same energy anyway (degenerate state)? Thanks! I super appreciate it!