Philipp Lenard

German physicist

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Philipp Eduard Anton von L é n á rd (June 7, 1862 May 20, 1947), a German physicist, accepted the Nobel Prize for Physics in 1905.

Leonard is studying Cathode ray He has achieved outstanding results, for which he has Nobel Prize ； He found out by experiment photoelectric effect Important laws of; He also proposed a atomic structure Assumption. Leonard is like his contemporaries Thomson Is as famous as Rutherford experimental physicist But he opposed Einstein's Special relativity 。 Leonard is a Parochial nationalism He was a physics consultant to Hitler. Nevertheless, Leonard is still an excellent experimental physicist.

Chinese name: Philipp Lenard
Foreign name: Philipp Eduard Anton von Lénárd
Nationality: Hungary
one's native heath: Presburg, Hungary
date of birth: June 7, 1862
Date of death: May 20, 1947
University one is graduated from: Heidelberg University

Occupation: physical scientist
Key achievements: Cathode ray
The Nobel Prize in Physics (1905)
Place of death: Messerhausen, Germany
Place of residence: Germany
Tutor: Robert Bunsen
Research institutions: Wroclaw University, Aachen University of Science and Technology

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Character's Life

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Philip Leonard in 1900

Philip Leonard was born on June 7, 1862 Hungary Presburg (now Slovakia Bratislava), parents from Austria Of Tyrol 。 He was in Budapest University 、 University of Vienna 、 University of Berlin and Heidelberg University Studying physics, once Bunsen 、 Helmholtz , Leo Koenigsberger and Georg Herman Kunke.

In 1886 Heidelberg University Obtained the title of doctor.

Since 1892, he has been a lecturer at the University of Bonn and an assistant to Professor Hertz.

In 1894, he was appointed Breslau University professor.

In 1895, it became Aachen University of Technology Professor of Physics.

1896 Heidelberg University Theoretical physics Professor.

Professor of Keele University in 1898.

Leonard joined the Nazi Party after Hitler came to power, criticized Jewish scientists and publicized Hitler's theory in public many times.

Obtained in 1905 The nobel prize in physics 。

1945 World War II After that, the United States, considering Leonard's old age, exempted him Denazification measures.

Leonard died in Messerhausen, Germany in 1947, and his legacy is now in Munich Of Deutsches Museum 。

Key achievements

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Cathode ray

In 1880, Leonard began to study cathode rays,

In 1892, Leonard, who was then Hertz's assistant, developed the crt The device can guide the cathode ray out of the ionization space, so as to further study the discharge process independently. Leonard measured the absorption of cathode rays by various samples. The results show that the absorption of cathode rays by objects is inversely proportional to their density, and the penetration ability of cathode rays in objects increases with the increase of voltage. Although Palin, Wayne and Thomson, like him, have confirmed that cathode rays are produced by negative electricity However, Leonard published "On the Electrostatic Properties of Cathode Rays" in 1898, which enabled him to make this discovery Priority 。

Leonard also found that high-energy cathode rays can pass through atoms. From this phenomenon, he correctly deduced that the space inside atoms is relatively empty. Later, Rutherford passed A particle scattering experiment The same evidence has also been obtained, and the commonly accepted Atomic nucleated model 。 In the study of light At launch Leonard believes that this is related to the release and return of electrons, and his view is just that Bohr atomic model It will be accepted by people after confirmation.

Leonard discovered photoelectric effect Important properties of: photoelectron The number increases with the intensity of light, but the kinetic energy of photoelectrons is only related to the frequency of light, not the intensity of light.

Cathode ray

In 1888, Leonard Heidelberg University Kunke worked under him. He completed his first research achievement on cathode ray. He studied Hertz's relationship between cathode ray and ultraviolet rays And designed an experiment to explore whether cathode rays, like ultraviolet rays, can pass The discharge tube On the wall of the quartz window, he obtained the result that cathode rays do not have such characteristics.

In 1892, he University of Bonn As Hertz's assistant, Hertz let him observe his new discovery, and Hertz covered one piece aluminum foil When the cathode ray bombards the aluminum foil, the light below the aluminum foil emits. Hertz therefore suggests that the space in the discharge tube can be divided into two parts by aluminum sheet. In one part of the space, cathode rays are generated by conventional methods, while in the other part of the space, cathode rays can be observed under vacuum conditions. Because Hertz was too busy, he authorized Leonard to do this experiment. Later, he got the important discovery of "Leonard Window".

After experimenting with different thicknesses of aluminum foil, Leonard finally published his important discovery in 1894 that the quartz plate used to seal the discharge tube can be replaced by aluminum foil. The thickness of the aluminum foil is just enough to maintain the vacuum state in the discharge tube, but it must be thin enough to allow cathode rays to pass through, so that not only can cathode rays be studied, It can also study the effect of cathode rays Fluorescence phenomenon 。 Leonard concluded from experiments that cathode rays can only travel decimetres in air, but can travel several meters without attenuation in vacuum. After Hertz claimed in 1892 that cathode rays could not be particles, but only an ether wave, Leonard agreed, but later Jean Baptiste Perrin (1895) Joseph Thomson (1897) and Wilhelm Wien Leonard gave up this view after his research results (1897) proved the particle characteristics of cathode rays. Thompson finally came to the conclusion that cathode rays are composed of negatively charged electrons.

photoelectric effect

After the photoelectric effect, Leonard continued to expand Hertz's research on photoelectric effect Vacuum environment The characteristics and essence of the photoelectric effect under Ultraviolet radiation When it is on the metal, it will make electrons escape from the metal surface and propagate in vacuum, and the electrons will be accelerated or decelerated in the electric field, Electron trajectory Change in a magnetic field. Through precise experiments, he proved the number of electrons emitted Proportional to incident light The energy carried, while the speed of electrons, or their kinetic energy Light energy The electron velocity increases when the wavelength of the incident light decreases. This fact conflicts with the theory at that time, Classical physics Leonard's photoelectric effect experiment results cannot be explained.

Until Einstein published in 1905 relativity And light Quantum Theory , which was later explained by Robert Andrews Millikan It has been proved that because people put Einstein's name on Light quanta In theory, Leonard has always been bitter about Einstein.

In the process of research, Leonard also invented a Photocell To accelerate electrons and measure their energy. This photocell is triode The original prototype is different in that in Leonard's photocell, electrons are emitted by the cathode light, while the cathode in the triode is an incandescent wire, which can emit higher intensity current into the vacuum. Leonard proposed in 1902 that when an electron passes through a gas, it must have a certain minimum energy to produce ionization of the gas.

Dynamo Atomic model

Dynamon atom model

Dynamon atom model Leonard proposed an atom in 1903 Structural model He called them "dynamides" (English: dynamides). They are small in size and scattered in a wide space. They have mass and are composed of many Galvanic couple The number of pairs (two electrons with the same charge and opposite charged symbols are connected) is equal to the mass of the atom.

He thought that the solid part of the atom only accounted for the whole Atomic volume One billionth of that, the dynaon atom model can explain the role of the Leonard window, but can't explain more facts, so it is a Unsuccessful The atomic model of. But Leonard's research Hendrick Lorenz Our electronic theory has contributed a lot.

Post research

Philipp Lenard

Later in Philip Leonard's life, Leonard studied Spectral line The essence of Rydberg Heinrich Kayser and Carl Runge proposed that the spectral lines of metals can be divided into two or more categories Continuous spectrum (pedigree), and there is an obvious mathematical relationship between the wavelengths of these pedigrees.

Leonard believed that there would be certain changes of atoms in each pedigree, which determined each pedigree and could be distinguished according to the number of electrons lost by atoms. Leonard is a genius experimental physicist He made many important discoveries, but when he announced the importance of these discoveries, they exceeded their real value, and he constantly clashed with other scientists. Although he has won many honors, such as university of oslo (1911) Dresden University (1922) and Bratislava University (1942) Honorary doctorate 、 Franklin Medal (1905) German Empire The Eagle Shield Medal (1933), and was elected Heidelberg's honorary citizen (1933), he still felt that he was not highly appraised, so he would attack other physicists in many countries.

Deutschen Physik

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Leonard from the anti Semitic Racism From the standpoint, since 1920, he has criticized Albert Einstein, a Jewish scientist, and advocated the so-called“ Germany Physics ".

After Hitler came to power, Leonard joined Nazi Party He became a very loyal scientific adviser to Hitler and advocated his racist and anti Semitic theories. In return, the Nazi Party regarded Leonard as the leader of Aryan or German physics and the agent of the Nazi in the field of physics.

Leonard's works include: About Ether and Materials (the second edition in 1911), Quantitative Analysis of Cathode Ray (1918), About Relativity (1918), and The Great Natural Science Researcher (the second edition in 1930).^[1]

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