question_answer 39)

  What is the minimum energy that must be given to a H atom in ground state so that it can emit an   line in Balmer series. If the angular momentum of the system is conserved, what would be the angular momentum of such photon?

Answer:

                   line in Balmer series corresponds to transition from n = 5 to n = 2. Therefore, electron in ground state (n = 1), must be raised first to the state (n = 5). Energy required for this purpose If the angular momentum of the system is conserved, then angular momentum of photon emitted = change in angular momentum of electron