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They were first observed in 1859 by German physicist Julius Plücker and Johann Wilhelm Hittorf, [1] and were named in 1876 by Eugen Goldstein Kathodenstrahlen, or cathode rays. [2] [3] In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the ...
Before Thomson's model, atoms were simply the basic units of weight by which the chemical elements react. Thomson himself was a physicist and his atomic model was a byproduct of his investigations of cathode rays, by which he discovered the negatively charged particles now known as electrons. Thomson hypothesized that the quantity, arrangement ...
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.
The cathode-ray tube by which J. J. Thomson demonstrated that cathode rays could be deflected by a magnetic field, and that their negative charge was not a separate phenomenon While supporters of the aetherial theory accepted the possibility that negatively charged particles are produced in Crookes tubes , [ citation needed ] they believed that ...
In 1897, J. J. Thomson succeeded in measuring the mass-to-charge ratio of cathode rays, showing that they consisted of negatively charged particles smaller than atoms, the first "subatomic particles", which had already been named electrons by Irish physicist George Johnstone Stoney in 1891.
The cathode is negatively charged and consists of a focusing cup made of nickel and two filaments made of tungsten. The filament is a coil of tungsten of a specified size (usual large and small). When current passes through the wire, heat is produced and causes the filament to release or burn off electrons. This is known as thermionic emission ...
Crookes was also able to show that the particles in the cathode rays were negatively charged and could be deflected by an electromagnetic field. [21] [18] In 1897, Joseph Thomson measured the mass of these cathode rays, [22] proving they were made of particles.
In 1897, J. J. Thomson succeeded in measuring the mass-to-charge ratio of cathode rays, showing that they consisted of negatively charged particles smaller than atoms, the first "subatomic particles", which had already been named electrons by Irish physicist George Johnstone Stoney in 1891.