Student Education Repository (மாணவர்கள் கல்விக் களஞ்சியம்): Today (June 7, 1862) is the birthday of Philipp Eduard von Lenard, winner of the Nobel Prize for his research on negative (cathode) rays and their properties.

Monday, June 7, 2021

Today (June 7, 1862) is the birthday of Philipp Eduard von Lenard, winner of the Nobel Prize for his research on negative (cathode) rays and their properties.

Today (June 7, 1862) is the birthday of Philipp Eduard von Lenard, winner of the Nobel Prize for his research on the negative (cathode) rays and their properties.

Philipp Eduard Anton von Lenard was born on June 7, 1862 in Bratislava, Hungary. The Lenard family first came from Tyrol in the 17th century. Lenard's parents were German speakers. His father, Philippe Von Lenardis, was a liquor dealer in Pressburg. His mother was Anthony Bauman. Young Lenard Possoni studied at the Crawley Catholicos Fogymnasium. And as he writes this in his autobiography, it had a huge impact on him. In 1880, he studied physics and chemistry in Vienna and Budapest. In 1882, Lenard left Budapest and returned to Pressburg. But in 1883 he moved to Heidelberg after the tender for the post of assistant at the University of Budapest was rejected. In Heidelberg, he studied under the famous Robert Bunsen. Hermann von Helmholtz interrupted for a semester in Berlin. He also received his doctorate in 1886.

Finally, in 1907, Philip Lenard returned to the University of Heidelberg as President of the Institute. In 1905, Lenard became a member of the Royal Swedish Academy of Sciences. In 1907 he became a member of the Hungarian Academy of Sciences. His early works included studies on phosphorescence and luminescence and the conductivity of flames. As a physicist, Lenard's major contributions were to the study of rays with the cathode, which he began in 1888. Before his work, cathode rays were produced in primitive, partially extruded glass tubes. They had metal electrodes on which high voltage could be placed. Cathode rays are difficult to study using this arrangement. Because they were inside sealed glass tubes. Since it was difficult to access, and the rays were in the presence of air molecules, Lenard overcame these problems by devising a method of making small metal windows out of glass.

The Quantised World

They were thick enough to withstand pressure differences. But were thin enough to allow the rays to pass. He created a window for the rays, which he could send them out of the laboratory, or, alternatively, into another room where they were completely expelled. These windows are known as Lenard windows. He was able to conveniently detect the rays and measure their intensity through sheets of paper coated with phosphorescent materials. Lenard observed that the absorption of rays by the cathode is proportional to the density of the material through which they pass. They seemed to contradict the notion of some kind of electromagnetic radiation. He also showed that the rays could pass through a few inches of air of a normal density. And they seemed to be scattered. This means that they must be particles that are smaller than molecules in the air. He has some of J.J. Thomson's work eventually led to the realization that cathode rays were streams of energetically charged particles.

After Helmholtz, he called them electricity or short quanta. At the same time, J.J. Thompson proposed the name Corpuscles. But eventually, electrons became every day. Along with his and other previous experiments on absorbing rays in metals, the general realization that electrons were part of the atom helped Lenard correctly state that most atoms have empty space. Each atom has an empty space and electrically neutral corpuscles called "dynamites". He proposed that each had an electron and an equivalent positive charge.

Canal Rays GIF | Gfycat

As a result of his Crookes tube investigation, he showed that the rays produced by irradiating metals in a vacuum with ultraviolet light are similar in many respects to cathode rays. His most important observations were that the energy of the rays was independent of light intensity. But it was more for short wavelengths of light. These latter observations were explained by Albert Einstein as a quantum effect. This theory predicts that the plot of cathode ray energy against frequency will be a straight line with a slope equal to Planck's constant. It was shown like this a few years later.

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Photo-electric quantum theory was quoted when Einstein was awarded the Nobel Prize in Physics. Lenard became skeptical of Einstein's general reputation and became a major skeptic of relativity and Einstein's theories. However, he did not deny Einstein's explanation of the effect of opacity. Winner of the Nobel Prize in Physics in 1905 for his research on cathode rays and their properties. In 1892 Lenard was the first person to read what was called the Lenard effect. This is the separation of electric charges with the aerodynamic breakdown of water droplets. This is also known as spray electrification or waterfall effect. He carried out studies on the size and shape distribution of raindrops. Created a new air tunnel. Water droplets of various sizes can last for a few seconds. He was the first to recognize that large raindrops are not teardrop-shaped but rather hamburger-shaped.

He pursued an anti-Semitic policy. He openly declared his support for Nazism and Idler in the 1920s. Albert called Einstein's contributions to physics "Jewish physics." Lenard retired from the University of Heidelberg in 1931 as a Professor of Theoretical Physics. He received Emeritus status there. But he was removed from his post in 1945 at the age of 83. Nobel laureate Philipp Eduard von Lenard passed away on May 20, 1947, at the age of 84 in Messelhausen, Germany.

Source By: Wikipedia

Information: Ramesh, Assistant Professor of Physics, Nehru Memorial College, Puthanampatti, Trichy.