The Photoelectric Effect and the Electron Charge

The idea of quantization advanced by M. Planck[aut]Planck, Max was resumed and relaunched in 1905 by A. Einstein[aut]Einstein, Albert, in the context of his studies on the creation and conversion of light, which include the photoelectric effect. In this chapter, we will discuss the steps that led to the discovery of the photoelectric effect, through the experimental studies conducted by H. Hertz[aut]Hertz, Heinrich, W. Hallwachs[aut]Hallwachs, Wilhelm and A. Righi[aut]Righi, Augusto. Moreover, we will deal with what P. Lenard[aut]Lenard, Philipp Eduard Anton von really measured and analyse in detail what was the interpretation of the photoelectric effect given by Einstein. Finally, we will describe the experimental validation given to Einstein’s heuristic model by R. Millikan[aut]Millikan, Robert Andrews in 1916, together with his work on the determination of electronic charge.