Henri Becquerel
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Henri Becquerel (1852-1908), French physicist and discoverer of radioactivity. Educated at the Ecole Polytechnique in Paris, he became professor of physics in 1895. In 1896 Becquerel discovered the phenomenon of radioactivity by showing that a uranium salt was able to blacken a wrapped photographic plate. In 1899 he noted that the radiation coming from the uranium salt was deflected by a magnetic field. Becquerel concluded that this radiation was partly composed of charged particles. He also discovered that radiation is toxic when he burnt his skin after leaving a radioactive source in his pocket. Becquerel shared the 1903 Nobel Prize in physics.