General Conception of the Quantum Theory

By consideration of Planck s formula W0=Av, Einstein was led to interpret phenomena of another type in terms of the quantum theory, thus giving rise to a new conception of this equation which has proved very fruitful. The phenomenon in question is the photoelectric effect. If light of frequency v falls on a metallic surface,4 electrons are set free and it is found that the intensity of the light influences 

4 When the symbols v and v are employed concurrently, v always refers to the frequency of the radiation, the symbol r to a frequency within the atom. (Translator s note.) 

We have then an electron, loosely bound in the metal, ejected by the incident light of frequency P and receiving the kinetic energy hv the atomic process is thus entirely different from that in the case of the resonator, and does not contain a frequency at all. The essential point appears to be, that the alteration in the energy of an atomic system is connected with the frequency of a light-wave by the equation 

Taking into account the new experiments by Bothe and Geiger, and by Compton and Simon, which have been mentioned above, we have to assume that the frequency P is radiated during the transition and the waves carry with them precisely the energy hv 

If Bohr s frequency relation (1) be applied to the resonator we are faced by alternatives which will now be considered. The change of energy which takes place when the resonator passes from the state with the energy njiv to that with the energy njiv, viz.  

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