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The current in a beam of cathode rays through a vacuum tube can be controlled by passing it through a metal screen of wires (a grid) between cathode and anode, to which a small negative voltage is applied. The electric field of the wires deflects some of the electrons, preventing them from reaching the anode.
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 ...
A cathode-ray tube (CRT) is a vacuum ... Hittorf observed that some unknown rays were emitted from the cathode (negative electrode) ... since the charge would repel ...
Irish physicist George Johnstone Stoney named this charge "electron" in 1891, and J. J. Thomson and his team of British physicists identified it as a particle in 1897 during the cathode-ray tube experiment. [5] Electrons participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles.
In 1899 Thomson reiterated his atomic model in a paper that showed that negative electricity created by ultraviolet light landing on a metal (known now as the photoelectric effect) has the same mass-to-charge ratio as cathode rays; then he applied his previous method for determining the charge on ions to the negative electric particles created ...
In 1896, in Cambridge, Joseph John Thomson (1856-1940) began experiments on cathode rays. In Britain, physicists argued these rays were particles, but German physicists disagreed, thinking they were a type of electromagnetic radiation. Thomson showed that the cathode rays were particles with a negative charge and much smaller than an atom.
A conventional current describes the direction in which positive charges move. Electrons have a negative electrical charge, so the movement of electrons is opposite to that of the conventional current flow. Consequently, the mnemonic cathode current departs also means that electrons flow into the device's cathode from the external circuit. For ...
The first attempt to measure the mass-to-charge ratio of cathode ray particles, assuming them to be ions, was made in 1884-1890 by German-born British physicist Arthur Schuster. He put an upper limit of 10^10 coul/kg, [ 5 ] but even that resulted in much greater value than expected, so little credence was given to his calculations at the time.