1. The problem statement, all variables and given/known data An electron is in a one-dimensional rectangular potential well with barriers of inﬁnite height. The width of the well is equal to L = 5 nm. Find the wavelengths of photons emitted during electronic transitions from the excited states with quantum numbers n = 2, λ21, and n = 3, λ31, to the ground state with n = 1. (Answer: λ21 ≈ 1.15 µm and λ31 ≈ 0.43 µm.) 2. Relevant equations E1 = (∏^2)*h^2/2meL^2 = 0.3737/L^2 eV ΔE = En+1 − En = (2n + 1)E1 ε = hf 3. The attempt at a solution I found the ground state energy to be 0.0149 eV. Then using the ΔE equation for n=2,3 I found the energies of the emitted photons to be 0.0745 eV and 0.1043 eV, respectively. Using these energies in plancks formula is getting me the wrong wavelengths, what am I doing wrong? Please help!