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Cathode rays are invisible, but their presence was first detected in these Crookes tubes when they struck the glass wall of the tube, exciting the atoms of the glass coating and causing them to emit light, a glow called fluorescence. Researchers noticed that objects placed in the tube in front of the cathode could cast a shadow on the glowing ...
In the 1870s, Goldstein undertook his own investigations of discharge tubes and named the light emissions studied by others Kathodenstrahlen, or cathode rays. [3] He discovered several important properties of cathode rays, which contributed to their later identification as the first subatomic particle, the electron. He found that cathode rays ...
A familiar example is the generation of light by an electron beam scanning the phosphor-coated inner surface of the screen of a television that uses a cathode-ray tube. Cathodoluminescence is the inverse of the photoelectric effect, in which electron emission is induced by irradiation with photons.
Canal ray (anode ray) tube In the mid-nineteenth century, Julius Plücker investigated the light emitted in discharge tubes and the influence of magnetic fields on the glow. [ 4 ] Later, in 1869, Johann Wilhelm Hittorf studied discharge tubes with energy rays extending from a negative electrode , the cathode.
The figure at the right shows the spectrum of a Franck–Hertz tube; nearly all of the light emitted has a single wavelength. For reference, the figure also shows the spectrum for a mercury gas discharge light, which emits light at several wavelengths besides 254 nm. The figure is based on the original spectra published by Franck and Hertz in 1914.
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 ...
He also investigated the light spectra of gases and vapours, worked on the passage of electricity through gases, and discovered new properties of cathode rays (electron rays). In 1869 he ascertained that the cathode rays glowed different colours because of different gasses and pressures.
Showed that cathode rays (1838), unlike light rays, can be bent in a magnetic field. 1885: Johann Balmer: Discovered that the four visible lines of the hydrogen spectrum could be assigned integers in a series: 1886: Henri Moissan: Isolated elemental fluorine after almost 74 years of effort by other chemists. 1886: Oliver Heaviside: Coined the ...