Alexandre-Edmond Becquerel (24.03.1820-02.05.1891) was a French physicist and a member of the Paris Academy of Sciences (1863), its president in 1880. He was the son of A. C. Becquerel. He was born in Paris. In 1840 he received the degree of doctor at the University of Paris and was an assistant there, while in 1849-52 he was also professor at the Agronomic Institute at Versailles. From 1852 he was head of the chair of physics at the Conservatoire des Arts et Métiers, and from 1878 director of the Museum of Natural History (Paris).
His work was in the fields of electricity, magnetism and optics (luminescence, phosphorescence, spectroscopy). He measured the e.m.f. of galvanic cells, studied electrochemical processes and the polarisation of electrodes while cells are working. He discovered (1851) the photogalvanic effect. In 1843 he proved that the Joule–Lenz law holds for conducting liquids. In 1845-55 he studied diamagnetism. In 1842 he obtained the first successful photograph of the solar spectrum, and in 1843 he discovered the Fraunhofer lines in the ultraviolet part of the spectrum. He carried out a series of studies of phosphorescence. He drew up a classification of the phenomena of phosphorescence and established the laws of the decay of phosphorescent emission, the independence of the spectrum of that emission from the spectrum of the irradiation, and the dependence of the intensity of phosphorescence on temperature. He discovered (1842) the property of infrared rays of inducing phosphorescence. He invented (1865) the phosphoroscope.