1. The problem statement, all variables and given/known data What wavelengths will be emitted if you bombard hydrogen gas (in its ground state) with 13 eV electrons. 2. Relevant equations 3. The attempt at a solution I talked to my professor about this one and he mumbled something about the ratio of the energies. I know the ground state energy is -13.6 eV and it's getting hit with 13 eV electrons. The ratio is 13/-13.6 = -.956 Or, I was reading that I should add the energies and then find the wavelength. Either way, the wavelength is pretty tiny..... Can I get a hint at what to do?