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He estimated the mass of cathode rays by measuring the heat generated when the rays hit a thermal junction and comparing this with the magnetic deflection of the rays. His experiments suggested not only that cathode rays were over 1,000 times lighter than the hydrogen atom, but also that their mass was the same in whichever type of atom they ...
A beam of cathode rays being bent by a magnetic field. Cathode rays are normally invisible; the path of this beam is revealed by having it strike a card with a fluorescent coating. By the 1870s, British physicist William Crookes and others were able to evacuate tubes to a lower pressure, below 10 −6 atm. These were called Crookes tubes.
Crookes X-ray tube from around 1910 Another Crookes x-ray tube. The device attached to the neck of the tube (right) is an "osmotic softener". When the voltage applied to a Crookes tube is high enough, around 5,000 volts or greater, [16] it can accelerate the electrons to a high enough velocity to create X-rays when they hit the anode or the glass wall of the tube.
Atoms were thought to be the smallest possible division of matter until 1899 when J. J. Thomson discovered the electron through his work on cathode rays. [ 37 ] : 86 [ 5 ] : 364 A Crookes tube is a sealed glass container in which two electrodes are separated by a vacuum.
They had attempted to generate an electrical signal by projecting an image onto a selenium-coated metal plate that was simultaneously scanned by a cathode ray beam. [2] [16] These experiments were conducted before March 1914, when Minchin died, [17] but they were later repeated by two different teams in 1937, by his students H. Miller and J. W ...
Later these particles were identified with the electron, discovered in cathode ray experiments by J. J. Thomson in 1897. This was connected with the theoretical prediction of the electromagnetic mass by J. J. Thomson in 1881, who showed that the electromagnetic energy contributes to the mass of a moving charged body. [2]
Thomson's experiments with cathode rays (1897): J. J. Thomson's cathode ray tube experiments (discovers the electron and its negative charge). Eötvös experiment (1909): Loránd Eötvös publishes the result of the second series of experiments, clearly demonstrating that inertial and gravitational mass are one and the same.
In 1869, Plücker's student Johann Wilhelm Hittorf found that a solid body placed between the cathode and the phosphorescence would cast a shadow on the tube wall, e.g. Figure 3. [18] Hittorf inferred that there are straight rays emitted from the cathode and that the phosphorescence was caused by the rays striking the tube walls.