Hi! The infinity to ground state return is associated with the very upper end of the Lyman series which corresponds to Ultra Violet radiation (frequency ~ 3.25 PHz) I hope this helps! Please don\'t forget to rate : ) Solution Hi! The infinity to ground state return is associated with the very upper end of the Lyman series which corresponds to Ultra Violet radiation (frequency ~ 3.25 PHz) I hope this helps! Please don\'t forget to rate : ).