Henri Becquerel

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Antoine Henri Becquerel
Antoine Becquerel, French physicist
Antoine Becquerel, French physicist
Born 15 December 1852(1852-12-15)
Paris, France
Died 25 August 1908 (aged 55)
Le Croisic, Brittany, France
Nationality France
Fields Physics, chemistry
Institutions Conservatoire des Arts et Metiers
École Polytechnique
Muséum National d'Histoire Naturelle
Alma mater École Polytechnique
École des Ponts et Chaussées
Doctoral students Marie Curie
Known for Radioactivity
Notable awards Nobel Prize in Physics (1903)
Religious stance Roman Catholic
Notes
Note that he is the father of Jean Becquerel, the son of A. E. Becquerel, and the grandson of Antoine César Becquerel.

Antoine Henri Becquerel (15 December 1852 – 25 August 1908) was a French physicist, Nobel laureate, and one of the discoverers of radioactivity. He won the 1903 Nobel Prize in Physics for discovering radioactivity.

Contents

[edit] Biography

[edit] Early life

Becquerel was born in Paris into a family which, including him and his son Jean, produced four generations of scientists. He studied science at the École Polytechnique and engineering at the École des Ponts et Chaussées. In 1890 he married Louise Désirée Lorieux

[edit] Career

In 1892, he became the third in his family to occupy the physics chair at the Muséum National d'Histoire Naturelle. In 1894, he became chief engineer in the Department of Bridges and Highways.

In 1896, while investigating phosphorescence in uranium salts, Becquerel accidentally discovered radioactivity. Investigating the work of Wilhelm Conrad Röntgen, Becquerel wrapped a fluorescent substance, potassium uranyl sulfate, in photographic plates and black material in preparation for an experiment requiring bright sunlight. However, prior to actually performing the experiment, Becquerel found that the photographic plates were fully exposed. This discovery led Becquerel to investigate the spontaneous emission of nuclear radiation.

Describing his method to the French Academy of Sciences on 24 January 1896, he said:

One wraps a Lumière photographic plate with a bromide emulsion in two sheets of very thick black paper, such that the plate does not become clouded upon being exposed to the sun for a day. One places on the sheet of paper, on the outside, a slab of the phosphorescent substance, and one exposes the whole to the sun for several hours. When one then develops the photographic plate, one recognizes that the silhouette of the phosphorescent substance appears in black on the negative. If one places between the phosphorescent substance and the paper a piece of money or a metal screen pierced with a cut-out design, one sees the image of these objects appear on the negative. … One must conclude from these experiments that the phosphorescent substance in question emits rays which pass through the opaque paper and reduces silver salts.[1][2]

In 1903, he shared the Nobel Prize in Physics with Pierre and Marie Curie "in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity".

[edit] Honours and awards

Image of Becquerel's photographic plate which has been fogged by exposure to radiation from a uranium salt. The shadow of a metal Maltese Cross placed between the plate and the uranium salt is clearly visible.
Image of Becquerel's photographic plate which has been fogged by exposure to radiation from a uranium salt. The shadow of a metal Maltese Cross placed between the plate and the uranium salt is clearly visible.

In 1908, the year of his death, Becquerel was elected Permanent Secretary of the Académie des Sciences. He died at the age of 55 in Le Croisic.

The SI unit for radioactivity, the becquerel (Bq), is named after him, and there is a Becquerel crater on the Moon and a Becquerel crater on Mars.

[edit] See also

[edit] References

  1. ^ Henri Becquerel (1896), "Sur les radiations émises par phosphorescence", Comptes Rendus 122: 420–421, <http://gallica.bnf.fr/ark:/12148/bpt6k30780/f422.chemindefer> 
  2. ^ Comptes Rendus 122, 420 (1896), translated by Carmen Giunta. Accessed 10 September 2006.

[edit] External links

Persondata
NAME Becquerel, Antoine Henri
ALTERNATIVE NAMES
SHORT DESCRIPTION French physicist
DATE OF BIRTH 15 December 1852
PLACE OF BIRTH Paris, France
DATE OF DEATH 25 August 1908
PLACE OF DEATH Le Croisic, Brittany, France
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