In 1900, Becquerel measured the mass-to-charge ratio (m/e) for beta particles by the method of J.J. Thomson used to study cathode rays and identify the electron.
No 1900, Becquerel mediu a relación masa-carga (m/e) para as partículas beta polo método de J.J. Thomson, usado para estudar os raios catódicos e identificar o electrón.