Philipp Eduard Anton von Lenard (Hungarian: Lénárd Fülöp Eduárd Antal; 7 June 1862 – 20 May 1947) was a Hungarian-born German physicist and the winner of the Nobel Prize for Physics in 1905 for his work on cathode raysand the discovery of many of their properties. One of his most important contributions was the experimental realization of the photoelectric effect. He discovered that the energy (speed) of the electrons ejected from a cathode depends only on the wavelength, and not the intensity, of the incident light.
Lenard was a nationalist and anti-Semite; as an active proponent of the Nazi ideology, he supported Adolf Hitler in the 1920s and was an important role model for the "Deutsche Physik" movement during the Nazi period. Notably, he labeled Albert Einstein's contributions to science as "Jewish physics".
Philipp Lenard | |
|---|---|
 Philipp Lenard in 1900 | |
| Born | Philipp Eduard Anton von Lenard 7 June 1862 |
| Died | 20 May 1947 (aged 84) |
| Citizenship | Hungarian[1] (1862–1907) German (1907–1947) |
| Alma mater | University of Heidelberg |
| Known for | Cathode rays |
| Spouse(s) | Katharina Schlehner |
| Awards | Matteucci Medal (1896) Rumford Medal (1896) Nobel Prize for Physics (1905) |
| Scientific career | |
| Fields | Physics |
| Institutions | University of Budapest University of Breslau University of Aachen University of Heidelberg University of Kiel University of Berlin |
| Doctoral advisor | R. Bunsen G. H. Quincke |
Lenard observed that the absorption of cathode rays was, to first order, proportional to the density of the material they were made to pass through. This appeared to contradict the idea that they were some sort of electromagnetic radiation. He also showed that the rays could pass through some inches of air of a normal density, and appeared to be scattered by it, implying that they must be particles that were even smaller than the molecules in air. He confirmed some of J. J. Thomson's work, which eventually arrived at the understanding that cathode rays were streams of negatively charged energetic particles. He called them quanta of electricity or for short quanta, after Helmholtz, while Thomson proposed the name corpuscles, but eventually electrons became the everyday term.[7] In conjunction with his and other earlier experiments on the absorption of the rays in metals, the general realization that electrons were constituent parts of the atom enabled Lenard to claim correctly that for the most part atoms consist of empty space. He proposed that every atom consists of empty space and electrically neutral corpuscules called "dynamids", each consisting of an electron and an equal positive charge.
As a result of his Crookes tube investigations, he showed that the rays produced by irradiating metals in a vacuum with ultraviolet light were similar in many respects to cathode rays. His most important observations were that the energy of the rays was independent of the light intensity, but was greater for shorter wavelengths of light.[8]
Lenard is remembered today as a strong German nationalist who despised "English physics", which he considered to have stolen its ideas from Germany.[13][14][15]During the Nazi regime, he was the outspoken proponent of the idea that Germany should rely on "Deutsche Physik" and ignore what he considered the fallacious and deliberately misleading ideas of "Jewish physics", by which he meant chiefly the theories of Albert Einstein, including "the Jewish fraud" of relativity (see also criticism of the theory of relativity).[16] An advisor to Adolf Hitler, Lenard became Chief of Aryan Physics under the Nazis.[17]
https://en.wikipedia.org/wiki/Philipp_Lenard
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