Hi, I'm having trouble on the following question: A singly ionized helium atom is in the ground state. It absorbs energy and makes a transition to the n = 3 excited state. The ion returns to the ground state by emitting two photons. What are the wavelengths of the lowest energy photon and highest energy photon? I think I have to use the conservation of energy approach where nf=1 and ni=3, and also account for the energy lost to the photon. But, I'm lost of how to actually do this, and how to differentiate between the lowest energy photon and highest energy photon (I figure it has something to do with the length of the wavelength - longer wavelength leading to less energy, and vice-versa). Thanks for your help!