, the loss in passing from the third to the second is
, i.e.
; and so on. It will be noticed that the numbers that come here are the same as those that occurred in connection with Rydberg’s constant in the preceding chapter.
The energy which is lost by the atom in one of these jumps is turned into a light-wave. What sort of light-wave it is to become is determined by the theory of quanta. A light-wave is a periodic process, and if its frequency is
, its period is a
