Rudolf Kohlrausch

He was a native of Göttingen, the son of the Royal Hanovarian director general of schools Friedrich Kohlrausch. He was a high-school teacher of mathematics and physics successively at Lüneburg, Rinteln, Kassel and Marburg. In 1853 he became an associate professor at the University of Marburg, and four years later, a full professor of physics at the University of Erlangen.[https://de.wikisource.org/wiki/ADB:Kohlrausch,_Rudolf ADB:Kohlrausch, Rudolf] @ Allgemeine Deutsche Biographie

In 1854 Kohlrausch introduced the relaxation phenomena, and used the stretched exponential function to explain relaxation effects of a discharging Leyden jar (capacitor).{{cite journal | pmc= 3557157 | pmid=23148417 | doi=10.1186/1471-2105-13-296 | volume=13 | title=Quantitative fluorescence loss in photobleaching for analysis of protein transport and aggregation | journal=BMC Bioinformatics | page=296 | last1 = Wüstner | first1 = D | last2 = Solanko | first2 = LM | last3 = Lund | first3 = FW | last4 = Sage | first4 = D | last5 = Schroll | first5 = HJ | last6 = Lomholt | first6 = MA| year=2012 | doi-access=free }}{{cite web |title=Blasts from the past |url=http://physicsworld.com/cws/article/print/18921 |website=physicsworld.com |archive-url=https://web.archive.org/web/20071128073958/http://physicsworld.com/cws/article/print/18921 |archive-date=28 November 2007 |date=28 November 2007 |url-status=dead}} In an 1855 experiment (published 1857) with Wilhelm Weber (1804–1891), he demonstrated that the ratio of electrostatic to electromagnetic units produced a number similar to the value of the speed of light,{{cite book |last1=Assis |first1=Andre Koch Torres |url=https://www.ifi.unicamp.br/~assis/Weber-Kohlrausch(2003).pdf |title=Volta and the History of Electricity |publisher=Universita degli Studi di Pavia and Editore Ulrico Hoepli |editor1-last=Bevilacqua |editor1-first=F |page=280 |chapter=On the First Electromagnetic Measurement of the Velocity of Light by Wilhelm Weber and Rudolf Kohlrausch |quote=Weber and Kohlrausch found √2 c = 4.39 x 10^8 m/s, such that c = 3.1 x 10^8 m/s |access-date=11 March 2023 |editor2-last=Giannetto |editor2-first=EA}} a constant which they named $c$. Kirchhoff recognized that the ratio is equal to $\backslash sqrt\; 2$ the speed of light.{{Cite journal |last=Mendelson |first=Kenneth S. |date=2006 |title=The story of c |url=https://pubs.aip.org/aapt/ajp/article/74/11/995-997/864528 |journal=American Journal of Physics |language=en |volume=74 |issue=11 |pages=995–997 |doi=10.1119/1.2238887 |bibcode=2006AmJPh..74..995M |issn=0002-9505}} This finding was instrumental towards Maxwell's conjecture that light is an electromagnetic wave.

He was the father of physicist Friedrich Kohlrausch.

• Elektrodynamische Maaßbestimmungen : insbesondere Zurückführung der Stromintensitäts-Messungen auf mechanisches Maass (with Wilhelm Weber) 1857. "Electrodynamic Measurements, Especially Attributing Mechanical Units to Measures of Current Intensity". [http://digital.slub-dresden.de/id299306070 German text]. [https://www.ifi.unicamp.br/~assis/Weber-EM4.pdf English translation]

• Kohlrausch function
• Kohlrausch volumetric flask

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• {{Cite Americana|wstitle=Kohlrausch, Rudolf Hermann Arndt}}
• {{Cite NIE|wstitle=Kohlrausch, Rudolf Hermann Arndt|year=1905 |short=x}}

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Category:1858 deaths

Category:1809 births

Category:Scientists from Göttingen

Category:19th-century German physicists

Category:Academic staff of the University of Erlangen-Nuremberg

Category:Academic staff of the University of Marburg

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