Lenard, Philipp

Lenard, Philipp, Grosse Naturfarsclier, J. F. Lehmanns Verlag, Munich,... 

In the course of his research on electromagnetic waves Hertz discovered the photoelectric effect. He showed that for the metals he used as targets, incident radiation in the ultraviolet was required to release negative charges from the metal. Research by Philipp Lenard, Wilhelm Hallwachs, J. J. Thomson, and other physicists finally led Albert Einstein to his famous 1905 equation for the photoelectric effect, which includes the idea that electromagnetic energy is quantized in units of hv, where h is Planck s con-... 

Hertz s last piece of experimental work was done when his health was deteriorating and he was devoting most of his research time to intensive theoretical work on the logical foundations of mechanics. In 1892 in his laboratoi-y in Bonn, he discovered that cathode rays could pass through thin metallic foils. He published a short paper on the subject, but did not pursue the matter further. Instead he handed his apparatus and his ideas over to Philipp Lenard (1862—1947), his assistant in Bonn. Lenard pushed Hertz s suggested research so far that Lenard received the Nobel Prize in Physics in 1905 for his work on cathode rays. ... 

A little earlier, in 1903 (Lenard 1903), Philipp Eduard Anton von Lenard (1862-1947) had carried out some scattering experiments in which he bombarded various metallic foils with high-energy cathode rays. He observed that the majority of electrons passed through the foils undeflected - from this he concluded that the majority of the volume occupied by the metallic atoms must be empty space. This idea was more fully developed by Rutherford (1911), who proposed the nuclear model of the atom which, despite much further elaboration, we still use today for the most basic explanations. 

The plum pudding model, a batter of positive charge with minute negative currants embedded in it, appeared to be consistent with experiments which showed that a beam of electrons could pass undeflected through a thin metallic foil. In other words, one might conclude, as Philipp Lenard (1862-1947) did in 1903, that the atom was mostly empty space. These data as well as the larger question about the inner structure of the atom prompted a most provocative line of experimentation by Ernest Rutherford (1871-1937). Manchester University was the site of these historical experiments, which Rutherford initiated soon after he arrived in 1907 to assume his responsibilities as Langworthy Professor of Physics. 

Philipp Lenard, German physicist, bom Pozsony, Austria-Hungary (now Bratislava, Slovakia), 1862. Ph.D. Heidelberg 1886. Professor, Heidelberg. Nobel prize in physics 1905, for work on cathode rays. Lenard supported the Nazis and rejected Einstein s dieory of relativity. Died Messelhausen, Germany, 1947. 

In 1902, the German physicist Philipp Eduard Anton Lenard (1862-1947) who, in earlier life, had been an assistant in Hertz s laboratory, showed that the photoelectric effect was brought about by the emission of electrons from metal. 

Charles H. Townes, Nicolay G. Basov, 1905 Philipp Lenard... 

Philipp Lenard - Biography. Nobelprize.org. Retrieved from http //nobelprize.org/nobel prizes/physics/laureates/1905/lenard-bio.html (Accessed August 14,2011). 

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