Thomson measured the mass of cathode rays, showing they were made of particles, but were around 1800 times lighter than the lightest atom, [Therefore, they were not atoms, but a new particle, the first
In 1705, it was noted that electrostatic generator sparks travel a longer distance through low pressure air than through atmospheric pressure air. ===Gas discharge tubes=== In 1838, Michael Faraday applied a high voltage between two metal electrodes at either end of a glass tube that had been partially evacuated of air, and noticed a strange light arc with its beginning at the cathode (negative electrode) and its end at the anode (positive electrode).
In 1857, German physicist and glassblower Heinrich Geissler sucked even more air out with an improved pump, to a pressure of around 10−3 atm and found that, instead of an arc, a glow filled the tube.
They were first observed in 1869 by German physicist Julius Plücker and Johann Wilhelm Hittorf, and were named in 1876 by Eugen Goldstein Kathodenstrahlen, or cathode rays.
In 1869, German physicist Johann Hittorf was first to realize that something must be traveling in straight lines from the cathode to cast the shadows.
This process is called fluorescence. ===Cathode rays=== By the 1870s, British physicist William Crookes and others were able to evacuate tubes to a lower pressure, below 10−6 atm.
They were first observed in 1869 by German physicist Julius Plücker and Johann Wilhelm Hittorf, and were named in 1876 by Eugen Goldstein Kathodenstrahlen, or cathode rays.
In 1897, British physicist J.
German scientists Eilhard Wiedemann, Heinrich Hertz and Goldstein believed they were "aether waves", some new form of electromagnetic radiation, and were separate from what carried the electric current through the tube. The debate was resolved in 1897 when J.
The triode vacuum tube developed between 1907 and 1914 was the first electronic device that could amplify, and is still used in some applications such as radio transmitters.
The triode vacuum tube developed between 1907 and 1914 was the first electronic device that could amplify, and is still used in some applications such as radio transmitters.
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