Biography

Entering the Polytechnique in 1873 at the age of 19, he emerged not in first place but in eighteenth, and joined the Ponts et Chaussées.His assignments in the Meuse and in Calvados gave no inkling that he would be recruited in 1876 by the Ecole Polytechnique as a physics tutor, while still a student engineer.In 1874, he married Lucie Jamin, daughter of Jules Jamin, a professor of physics at the École Polytechnique.Although he graduated as an engineer in 1877, he chose to follow his forebears into scientific research as a physicist.His main interest in his career was to be the structure of matter and the way in which this structure affects the magnetic and optical properties of bodies.His first work was on optics, but then from 1875 he joined his father Edmond Becquerel in research on magnetic rotatory polarisation, publishing the laws of this mechanism in 1875 and 1876 in the Proceedings of the Academy of Sciences.

He then worked on the emission spectra of incandescent metal vapours, on fluorescence and infrared radiation, but his main research interest remained electricity.In addition to his doctoral thesis of 1888, based on his research into the absorption of light by crystals, he published several papers on the subject and a book entitled Electro-chimie (Electrochemistry) in 1887.

In 1892, he succeeded his father in the chair of Physics at the French National Museum of Natural History, and in 1895 became Professor of Physics at the École Polytechnique. From this point he directed his research efforts to the phenomena of luminescence.Following on from Röntgen’s work on cathode rays, in 1896 he demonstrated the “radioactivity” of uranium (a term invented by Marie Curie to refer to the emission of radiation similar to that of uranium), working on fluorescence in uranium salts.His aim was to determine whether this phenomenon was of the same nature as x-rays. When studying a photographic plate in contact with the material, he noticed that an imprint was left even if the material was not exposed to sunlight. He concluded that the material emits its own radiation (known as Becquerel radiation) without needing to be activated by light.This work earned him the Rumford Medal in 1900. In 1903, Henri Becquerel was awarded the Nobel Prize for Physics “in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity”, shared with Pierre and Marie Curie for their discovery of polonium and radium.

Achievements

• 1896, In 1896, Henri Becquerel discovered spontaneous radioactivity.
• 1975, In 1975, the International System of Units decided to adopt the becquerel (symbol: Bq) for the activity of a radionuclide, which corresponds to one decay per second. It is equivalent to s-1, an inverse second. The activity of a substance is defined as the number of radioactive decays per second within a certain quantity of material.

Awards

• 1908, Rumford Medal
• 1903, Nobel Prize for Physics

Photo gallery

Links

• ENPC
• Prix Nobel

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