Alexander Grigorievich Stoletov (russian: Алекса́ндр Григо́рьевич Столе́тов; 10 August 1839 – 27 May 1896) was a

Russian Russian(s) refers to anything related to Russia, including: *Russians (, ''russkiye''), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *Rossiyane (), Russian language term for all citizens and peo ...

physicist, founder of electrical engineering, and professor in

Moscow University M. V. Lomonosov Moscow State University (MSU; russian: Московский государственный университет имени М. В. Ломоносова) is a public research university in Moscow, Russia and the most prestigious ...

. He was the brother of general

Nikolai Stoletov Nikolai Grigorevich Stoletov (russian: Столетов, Николай Григорьевич; – ) was a general in the Imperial Russian Army. He was the brother of noted physicist Aleksandr Stoletov. Stoletov was born in Vladimir and atte ...

Biography

Alexander Stoletov defended his doctoral dissertation in 1872 and became professor at

a year later. After defending his dissertation he became a renowned scientist worldwide. He attended the opening ceremony of the physical laboratory in Cambridge in 1874, and represented Russia at the first World Congress of Electricity in Paris in 1881, where he presented his work on links between electrostatic and electromagnetic values.

Contribution to science

His major contributions include pioneer work in the field of

ferromagnetism Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials a ...

and discovery of the laws and principles of the outer

photoelectric effect The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid stat ...

. Achievements of Alexander Stoletov include: Magnetism (1871–1872) * Stoletov was the first to show that with the increase of the magnetic field the magnetic susceptibility of iron grows, but then begins to decrease. * Built the curve of the magnetic permeability of ferromagnetics, known as the

Stoletov curve Stoletov curve shows the dependence of the magnetic permeability \chi of ferromagnetics on the intensity of the applied magnetic field ''H''. The curve is named after physicist Aleksandr Stoletov who analyzed in a long series of experiments the mag ...

. * Developed two new methods for measuring magnetic properties of various materials. Photoelectric effect (1888–1891) * Studied the outer

, discovered by Hertz in 1887. Published the results in six works. * Developed quantitative methods for the study of the photoelectric effect. * Discovered the direct proportionality between the intensity of light and the corresponding photo induced current ( Stoletov's law) * Discovered the Stoletov constant which defines the ratio between the intensity of the electric current and the gas pressure under the maximum current. * Built the first

solar cell A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.photoelectric current. * Discovered the decrease of the solar cell's sensitivity with time (fatigue of solar cells). Other * Calculated the proportion between electrodynamic and electrostatic units, producing a value very close to the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit fo ...

Publications

Important published works of Alexander Stoletov include: * On the Kohlrausch's measurement of the mercury unit of electric resistance; * Sur une méthode pour déterminer le rapport des unités électromagnétiques et électrostatiques; * On the electricity of juxtaposition; * On the critical state of bodies (4 articles); * Actino-electric research; * Ether and electricity; * Essay on the development of our knowledge of gases; * Introduction into acoustics and optics.

References

External links

Alexander Stoletov
at th
Russia InfoCentre
{{DEFAULTSORT:Stoletov Aleksandr Grigorievich 1839 births 1896 deaths People from Vladimir, Russia Physicists from the Russian Empire Inventors from the Russian Empire Russian electrical engineers Imperial Moscow University alumni Moscow State University faculty

Biography

Contribution to science

See also

Publications

References

External links