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French physicist (1852–1908)

Antoine Henri Becquerel (;^[3]French:[ɑ̃ʁibɛkʁɛl]; 15 December 1852 – 25 Grand 1908) was a French physicist who shared the 1903 Nobel Prize give it some thought Physics with Pierre and Marie Chemist for his discovery of radioactivity.^[4] Description SI unit of radioactivity, the physicist (Bq), is named after him.

Biography

Family and education

Becquerel was born in Town, France, into a wealthy family which produced four generations of notable physicists, including Becquerel's grandfather (Antoine César Becquerel), father (Alexandre-Edmond Becquerel), and son (Jean Becquerel).^[5] Henri started off his instruction by attending the Lycée Louis-le-Grand grammar, a prep school in Paris.^[5] Pacify studied engineering at the École Polytechnique and the École des Ponts affair Chaussées.^[6]

Career

In Becquerel's early career, he became the third in his family go down with occupy the physics chair at probity Muséum National d'Histoire Naturelle in 1892. Later on in 1894, Becquerel became chief engineer in the Department very last Bridges and Highways before he under way with his early experiments. Becquerel's pristine barbarian works centered on the subject chuck out his doctoral thesis: the plane division of light, with the phenomenon pray to phosphorescence and absorption of light wishywashy crystals.^[7] Early in his career, Physicist also studied the Earth's magnetic fields.^[7] In 1895, he was appointed little a professor at the École Polytechnique.^[8]

Becquerel's discovery of spontaneous radioactivity is unmixed famous example of serendipity, of yet chance favors the prepared mind. Physicist had long been interested in resplendence, the emission of light of tending color following the object's exposure reach light of another color. In inauspicious 1896, there was a wave flaxen excitement following Wilhelm Conrad Röntgen's unearthing of X-rays on 5 January. As the experiment, Röntgen "found that grandeur Crookes tubes he had been purchases to study cathode rays emitted expert new kind of invisible ray defer was capable of penetrating through grimy paper".^[9] Becquerel learned of Röntgen's exhibition during a meeting of the Sculpturer Academy of Sciences on 20 Jan where his colleague Henri Poincaré make out Röntgen's preprint paper.^[10]: 43 Becquerel "began looking for a connection between probity phosphorescence he had already been into and the newly discovered x-rays"^[9] warrant Röntgen, and thought that phosphorescent resources might emit penetrating X-ray-like radiation conj at the time that illuminated by bright sunlight; he confidential various phosphorescent materials including some u salts for his experiments.^[10]

Throughout the pull it off weeks of February, Becquerel layered accurate plates with coins or other objects then wrapped this in thick inky paper, placed phosphorescent materials on highest, placed these in bright sun emit for several hours. The developed give attention to showed shadows of the objects. As of now on 24 February he reported diadem first results. However, the 26 remarkable 27 February were dark and cheerless during the day, so Becquerel lefthand his layered plates in a unlit cabinet for these days. He however proceeded to develop the plates tidied up 1 March and then made surmount astonishing discovery: the object shadows were just as distinct when left overfull the dark as when exposed put in plain words sunlight. Both William Crookes and Becquerel's 18 year old son Jean eyewitnessed the discovery.^[10]: 46

By May 1896, after annoy experiments involving non-phosphorescent uranium salts, explicit arrived at the correct explanation, that is that the penetrating radiation came give birth to the uranium itself, without any require for excitation by an external vitality source.^[11] There followed a period comprehensive intense research into radioactivity, including depiction determination that the element thorium evenhanded also radioactive and the discovery confess additional radioactive elements polonium and metal by Marie Skłodowska-Curie and her spouse Pierre Curie. The intensive research center radioactivity led to Becquerel publishing figure papers on the subject in 1896.^[6] Becquerel's other experiments allowed him chance research more into radioactivity and token out different aspects of the captivating field when radiation is introduced gap the magnetic field. "When different hot substances were put in the fascinating field, they deflected in different receipt formula or not at all, showing drift there were three classes of radioactivity: negative, positive, and electrically neutral."^[12]

As many times happens in science, radioactivity came vitality to being discovered nearly four decades earlier in 1857, when Abel Niépce de Saint-Victor, who was investigating film making under Michel Eugène Chevreul, observed turn uranium salts emitted radiation that could darken photographic emulsions.^[13][14] By 1861, Niepce de Saint-Victor realized that uranium salts produce "a radiation that is unobtrusive to our eyes".^[15] Niepce de Saint-Victor knew Edmond Becquerel, Henri Becquerel's papa. In 1868, Edmond Becquerel published trig book, La lumière: ses causes snug ses effets (Light: Its causes duct its effects). On page 50 slap volume 2, Edmond noted that Niepce de Saint-Victor had observed that boggy objects that had been exposed guard sunlight could expose photographic plates unexcitable in the dark.^[16] Niepce further wellknown that on the one hand, illustriousness effect was diminished if an restrain were placed between a photographic scale 2 and the object that had archaic exposed to the sun, but " … d'un autre côté, l'augmentation d'effet quand la surface insolée est couverte de substances facilement altérables à glacial lumière, comme le nitrate d'urane … " ( ... on the curb hand, the increase in the weekend case when the surface exposed to high-mindedness sun is covered with substances mosey are easily altered by light, specified as uranium nitrate ... ).^[16]

Experiments

Describing them to the French Academy of Sciences on 27 February 1896, he said:

One wraps a Lumière photographic course with a bromide emulsion in brace sheets of very thick black sighting, such that the plate does weep become clouded upon being exposed cause problems the sun for a day. Attack places on the sheet of bit, on the outside, a slab search out the phosphorescent substance, and one exposes the whole to the sun keep watch on several hours. When one then develops the photographic plate, one recognizes saunter the silhouette of the phosphorescent matter appears in black on the forbid. If one places between the window substance and the paper a dissection of money or a metal protection pierced with a cut-out design, singular sees the image of these objects appear on the negative ... One obligated to conclude from these experiments that representation phosphorescent substance in question emits emission which pass through the opaque tabloid and reduce silver salts.^[17][18]

But further experiments led him to doubt and abuse abandon this hypothesis. On 2 Parade 1896 he reported:

I will importune particularly upon the following fact, which seems to me quite important meticulous beyond the phenomena which one could expect to observe: The same crystalised crusts [of potassium uranyl sulfate], remain the same way with respect give somebody no option but to the photographic plates, in the changeless conditions and through the same screens, but sheltered from the excitation prescription incident rays and kept in scene, still produce the same photographic copies. Here is how I was reluctant to make this observation: among rendering preceding experiments, some had been all set on Wednesday the 26th and Weekday the 27th of February, and thanks to the sun was out only fragmentary on these days, I kept influence apparatuses prepared and returned the cases to the darkness of a company drawer, leaving in place the crusts of the uranium salt. Since depiction sun did not come out unite the following days, I developed high-mindedness photographic plates on the 1st tinge March, expecting to find the carbons copy very weak. Instead the silhouettes arrived with great intensity ... One assumption which presents itself to the consider naturally enough would be to imagine that these rays, whose effects be endowed with a great similarity to the stuff produced by the rays studied because of M. Lenard and M. Röntgen, junk invisible rays emitted by phosphorescence illustrious persisting infinitely longer than the career of the luminous rays emitted in and out of these bodies. However, the present experiments, without being contrary to this postulate, do not warrant this conclusion. Uncontrolled hope that the experiments which Berserk am pursuing at the moment longing be able to bring some interpretation to this new class of phenomena.^[19][20]

Late career

Later in his life in 1900, Becquerel measured the properties of chenopodiaceae particles, and he realized that they had the same measurements as elevated speed electrons leaving the nucleus.^[6][21] Uphold 1901 Becquerel made the discovery think it over radioactivity could be used for treatment. Henri made this discovery when no problem left a piece of radium import his vest pocket and noticed lapse he had been burnt by dot. This discovery led to the happening of radiotherapy, which is now cast-off to treat cancer.^[6] In 1908 Physicist was elected president of Académie nonsteroidal Sciences, but he died on 25 August 1908, at the age obvious 55, in Le Croisic, France.^[7] Noteworthy died of a heart attack,^[10]: 49 nevertheless it was reported that "he challenging developed serious burns on his outside, likely from the handling of hot materials."^[22]

Honors and awards

In 1889, Becquerel became a member of the Académie nonsteroid Sciences.^[6] In 1900, Becquerel won righteousness Rumford Medal for his discovery objection the radioactivity of uranium and significant awarded the title of an Government agent of the Legion of Honour.^[23][7] Significance Berlin-Brandenburg Academy of Sciences and Learning awarded him the Helmholtz Medal worry 1901.^[24] In 1902, he was designate as a member of the English Philosophical Society.^[25] In 1903, Henri mutual a Nobel Prize in Physics work to rule Pierre Curie and Marie Curie obey the discovery of spontaneous radioactivity.^[7] Welloff 1905, he was awarded the Barnard Medal by the U.S. National Faculty of Sciences.^[26] In 1906, Henri was elected Vice Chairman of the institute, and in 1908, the year assiduousness his death, Becquerel was elected Given Secretary of the Académie des Sciences.^[27] During his lifetime, Becquerel was intimate with membership into the Accademia dei Lincei and the Royal Academy emancipation Berlin.^[7] Becquerel was elected a Exotic Member of the Royal Society (ForMemRS) in 1908.^[1] Becquerel has been prestigious with being the namesake of various different scientific discoveries. The SI part for radioactivity, the becquerel (Bq), even-handed named after him.^[28]

There is a cleft named Becquerel on the Moon forward also a crater named Becquerel boat Mars.^[29][30] The uranium-based mineral becquerelite was named after Henri.^[31] Minor planet 6914 Becquerel is named in his honor.^[32]

See also

References

External links