Other Free Encyclopedias » Online Encyclopedia » Encyclopedia - Featured Articles » Contributed Topics from A-E

Becquerel, (Antoine) Henri

radioactivity found physics light

[bekuhrel] (1852–1908) French physicist: discoverer of radioactivity.

Like his father and grandfather before him, Becquerel studied physics, and like them he was interested in fluorescence; he also succeeded to the posts they had held in Paris. Educated mainly at the École Polytechnique, he became professor of physics there in 1895. His crucial experiment of 1896 was performed on the day that news of discovery of X-rays reached Paris: Becquerel wondered if phosphorescent compounds emitted similar rays. He found that a uranium salt placed on a wrapped photographic plate caused this to blacken. He soon found that this did not require light; that it was due to the uranium only; and that the radiation was not reflected like light. He found it was able to ionize air. Although similar to the X-rays discovered in 1895 by Röntgen, it was not the same. His work was soon confirmed and was the starting point for all studies on radioactivity. He shared the Nobel Prize for physics in 1903 with the . His other studies, on magnetic effects and on light absorption by crystals, were valuable; but his work on radioactivity gave physics a new direction.

Radiotherapy (later used to treat cancer) began with his observation that radium carried in his pocket produced a burn. The SI unit of radioactivity is the becquerel (Bq), defined as an activity of one disintegration per second. Henri’s father Alexandre-Edmond Becquerel (1820–91) initiated photoelectrochemistry, when in 1839 he found that platinum electrodes, one in methanol and the other in aqueous ferric perchlorate, gave 0.1V on irradiation with sunlight. Subsequent interest in photovoltaic effects has focused on semiconductor devices.

Beddoes, Thomas [next] [back] Becon, Thomas (1512–1567) - BIOGRAPHY, MAJOR WORKS AND THEMES, CRITICAL RECEPTION

User Comments

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or