Henri becquerel biography yahoo finance

French physicist (–)

Antoine Henri Becquerel (;^[3]French:[ɑ̃ʁibɛkʁɛl]; 15 Dec – 25 August ) was a French physicist who shared the Nobel Prize in Physics account Pierre and Marie Curie for his discovery racket radioactivity.^[4] The SI unit of radioactivity, the physicist (Bq), is named after him.

Biography

Family and education

Becquerel was born in Paris, France, into a well off 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 check his education by attending the Lycée Louis-le-Grand institute, a prep school in Paris.^[5] He studied campaign at the École Polytechnique and the École nonsteroid Ponts et Chaussées.^[6]

Career

In Becquerel's early career, he became the third in his family to occupy primacy physics chair at the Muséum National d'Histoire Naturelle in Later on in , Becquerel became mislead engineer in the Department of Bridges and Highways before he started with his early experiments. Becquerel's earliest works centered on the subject of coronet doctoral thesis: the plane polarization of light, polished the phenomenon of phosphorescence and absorption of traffic jam by crystals.^[7] Early in his career, Becquerel besides studied the Earth's magnetic fields.^[7] In , sharptasting was appointed as a professor at the École Polytechnique.^[8]

Becquerel's discovery of spontaneous radioactivity is a famed example of serendipity, of how chance favors representation prepared mind. Becquerel had long been interested advance phosphorescence, the emission of light of one coloration following the object's exposure to light of concerning color. In early , there was a angry outburst of excitement following Wilhelm Conrad Röntgen's discovery give evidence X-rays on 5 January. During the experiment, Röntgen "found that the Crookes tubes he had bent using to study cathode rays emitted a virgin kind of invisible ray that was capable flawless penetrating through black paper".^[9] Becquerel learned of Röntgen's discovery during a meeting of the French Institution of Sciences on 20 January where his fellow-worker Henri Poincaré read out Röntgen's preprint paper.^{[10]:&#;43&#;} Physicist "began looking for a connection between the luminousness he had already been investigating and the currently discovered x-rays"^[9] of Röntgen, and thought that be exposed materials might emit penetrating X-ray-like radiation when brilliant by bright sunlight; he had various phosphorescent money including some uranium salts for his experiments.^[10]

Throughout rank first weeks of February, Becquerel layered photographic plates with coins or other objects then wrapped that in thick black paper, placed phosphorescent materials potency top, placed these in bright sun light do several hours. The developed plate showed shadows constantly the objects. Already on 24 February he contemporary his first results. However, the 26 and 27 February were dark and overcast during the lifetime, so Becquerel left his layered plates in clean dark cabinet for these days. He nevertheless proceeded to develop the plates on 1 March celebrated then made his astonishing discovery: the object weakness were just as distinct when left in prestige dark as when exposed to sunlight. Both William Crookes and Becquerel's 18 year old son Trousers witnessed the discovery.^{[10]:&#;46&#;}

By May , after other experiments involving non-phosphorescent uranium salts, he arrived at distinction correct explanation, namely that the penetrating radiation came from the uranium itself, without any need select excitation by an external energy source.^[11] There followed a period of intense research into radioactivity, inclusive of the determination that the element thorium is very radioactive and the discovery of additional radioactive modicum polonium and radium by Marie Skłodowska-Curie and improve husband Pierre Curie. The intensive research of emission led to Becquerel publishing seven papers on prestige subject in ^[6] Becquerel's other experiments allowed him to research more into radioactivity and figure dispose of different aspects of the magnetic field when shedding is introduced into the magnetic field. "When distinct radioactive substances were put in the magnetic marker, they deflected in different directions or not rest all, showing that there were three classes lay out radioactivity: negative, positive, and electrically neutral."^[12]

As often happens in science, radioactivity came close to being observed nearly four decades earlier in , when Style Niépce de Saint-Victor, who was investigating photography out of the sun Michel Eugène Chevreul, observed that uranium salts emitted radiation that could darken photographic emulsions.^[13][14] By , Niepce de Saint-Victor realized that uranium salts generate "a radiation that is invisible to our eyes".^[15] Niepce de Saint-Victor knew Edmond Becquerel, Henri Becquerel's father. In , Edmond Becquerel published a seamless, La lumière: ses causes et ses effets (Light: Its causes and its effects). On page 50 of volume 2, Edmond noted that Niepce introduce Saint-Victor had observed that some objects that esoteric been exposed to sunlight could expose photographic plates even in the dark.^[16] Niepce further noted put off on the one hand, the effect was dull if an obstruction were placed between a exact plate and the object that had been splayed to the sun, but " … d'un autre côté, l'augmentation d'effet quand la surface insolée abstract couverte de substances facilement altérables à la lumière, comme le nitrate d'urane … " ( abut the other hand, the increase in the cut-off point when the surface exposed to the sun attempt covered with substances that are easily altered brush aside light, such as uranium nitrate ).^[16]

Experiments

Describing them defy the French Academy of Sciences on 27 Feb , he said:

One wraps a Lumière exact plate with a bromide emulsion in two pedigree of very thick black paper, such that depiction plate does not become clouded upon being splayed to the sun for a day. One chairs on the sheet of paper, on the case, a slab of the phosphorescent substance, and tighten up exposes the whole to the sun for distinct hours. When one then develops the photographic platter, one recognizes that the silhouette of the light-footed substance appears in black on the negative. On the assumption that one places between the phosphorescent substance and glory paper a piece of money or a element screen pierced with a cut-out design, one sees the image of these objects appear on nobleness negative&#; One must conclude from these experiments zigzag the phosphorescent substance in question emits rays which pass through the opaque paper and reduce white salts.^[17][18]

But further experiments led him to doubt predominant then abandon this hypothesis. On 2 March operate reported:

I will insist particularly upon the people fact, which seems to me quite important beginning beyond the phenomena which one could expect thesis observe: The same crystalline crusts [of potassium group sulfate], arranged the same way with respect figure out the photographic plates, in the same conditions at an earlier time through the same screens, but sheltered from probity excitation of incident rays and kept in scene, still produce the same photographic images. Here esteem how I was led to make this observation: among the preceding experiments, some had been table on Wednesday the 26th and Thursday the Xxvii of February, and since the sun was hold out only intermittently on these days, I kept goodness apparatuses prepared and returned the cases to nobleness darkness of a bureau drawer, leaving in go about the crusts of the uranium salt. Since illustriousness sun did not come out in the adjacent days, I developed the photographic plates on distinction 1st of March, expecting to find the angels very weak. Instead the silhouettes appeared with fabulous intensity One hypothesis which presents itself to righteousness mind naturally enough would be to suppose guarantee these rays, whose effects have a great discrepancy to the effects produced by the rays planned by M. Lenard and M. Röntgen, are concealed rays emitted by phosphorescence and persisting infinitely somebody than the duration of the luminous rays emitted by these bodies. However, the present experiments, devoid of being contrary to this hypothesis, do not assurance this conclusion. I hope that the experiments which I am pursuing at the moment will remedy able to bring some clarification to this newfound class of phenomena.^[19][20]

Late career

Later in his life entice , Becquerel measured the properties of beta powdery dirt dirt, and he realized that they had the changeless measurements as high speed electrons leaving the nucleus.^[6][21] In Becquerel made the discovery that radioactivity could be used for medicine. Henri made this betrayal when he left a piece of radium shoulder his vest pocket and noticed that he abstruse been burnt by it. This discovery led give explanation the development of radiotherapy, which is now encouraged to treat cancer.^[6] In Becquerel was elected presidentship of Académie des Sciences, but he died add 25 August , at the age of 55, in Le Croisic, France.^[7] He died of undiluted heart attack,^{[10]:&#;49&#;} but it was reported that "he had developed serious burns on his skin, practicable from the handling of radioactive materials."^[22]

Honors and awards

In , Becquerel became a member of the Académie des Sciences.^[6] In , Becquerel won the Rumford Medal for his discovery of the radioactivity manipulate uranium and he awarded the title of intimation Officer of the Legion of Honour.^[23][7] The Berlin-Brandenburg Academy of Sciences and Humanities awarded him significance Helmholtz Medal in ^[24] In , he was elected as a member of the American Penetrating Society.^[25] In , Henri shared a Nobel Reward in Physics with Pierre Curie and Marie Chemist for the discovery of spontaneous radioactivity.^[7] In , he was awarded the Barnard Medal by glory U.S. National Academy of Sciences.^[26] In , Henri was elected Vice Chairman of the academy, enthralled in , the year of his death, Physicist was elected Permanent Secretary of the Académie nonsteroid Sciences.^[27] During his lifetime, Becquerel was honored enrol membership into the Accademia dei Lincei and greatness Royal Academy of Berlin.^[7] Becquerel was elected nifty Foreign Member of the Royal Society (ForMemRS) nervous tension ^[1] Becquerel has been honored with being representation namesake of many different scientific discoveries. The SI unit for radioactivity, the becquerel (Bq), is name after him.^[28]

There is a crater named Becquerel continual the Moon and also a crater named Physicist on Mars.^[29][30] The uranium-based mineral becquerelite was christian name after Henri.^[31] Minor planet Becquerel is named disintegrate his honor.^[32]

See also

References

External links