1. The problem statement, all variables and given/known data Consider a process of a capture of an electron into 2p1/2 and 2p3/2 states of hydrogen atom. Find a population ratio of these two states after the capture. 2. Relevant equations ? 3. The attempt at a solution I don't know where to start on this question. As far as I know, electron capture is a process where Inner electron is absorbed by a nucleus (proton or neutron), and not captured into a into 2p1/2 and 2p3/2 states. And what is meant by population ratio ?