Ahydrogen atom emits a photon of energy 1.89 ev- ry, where ry 13.6 ev, and 36 ends up in a 2p state(n=2, 1-1). what are the possible states the atom could have been in before it emitted the photon? (when an atom emits a photon, the value of l for the atomic state changes by t1.) you can use the traditional names for the states (such as 2p) or you can label them by their quantum numbers n and i. for each state on your list, state its degeneracy. b) in the copenhagen interpretation of quantum mechanics, quantum measurements correspond to what we call "strong measurements" in modern terminology. after a measurement is made, the quantum system supposedly "collapses" into the eigenstate of the measurement operator corresponding to the measured eigenvalue. a physicist measures the energy of the hydrogen atom in part (a) to confirm that the atom is in a 2p state with energy -ry/4, then he measures the z-component of angular momentum, l., and obtains the result -h. after that his colleague measures the atom's energy again. what are the possible results she will get, and with what probabilities? explain how you got your answer. you may assume that the atom does not emit or absorb a photon during the experiment.