From the perception of solid matter, it was presumed that this positive residual matter filled the entire space of the atom, giving rise to what has been called the " Thomson model" of the atom. So much so, that George Stoney (1891) proposed the name electron for the particle. Scientist had believed in the existence of a negative particle for some time. Thomson demonstrated the existence of the electron. It was known that electrons could be removed from atoms, and that they became positive ions as a result. The cathode ray tube experiment performed by J.J. With the combined results of Thomson and Millikan, a value for the electron mass was obtained - a value far below that of atoms. The determination of the charge of the electron awaited the work of Millikan who measured the electron charge in 1909 with his oil drop experiment. Using this apparatus, Thomson determined the charge-to-mass ratio of the electron, e/m. This same principle is presently used in velocity selectors for mass spectrometers. Thomson showed that with the application of both electric and magnetic fields, he could balance the deflections and obtain a straight beam. A narrow luminous beam could be produced by using an aperture near the cathode, and this beam could be deflected by either an electric field or a magnetic field. Thomson and Clinton Davisson demonstrated, independently of one another, that electrons could be described as waves. In the 1890's, cathode ray tubes had been developed in which a luminous beam could be produced in a partially evacuated glass tube, directed from the negative electrode (cathode) to the positive (anode). So, the cathode ray experiment is also commonly known as J.J. The above modified experiments were performed by J.J. ![]() This also helped scientists in finding the charge of electrons. ![]() Sir Joseph John Thomson (1856-1940) played a pivotal role in developing our understanding of the electron. Cathode rays also get deflected from their path if a magnetic field is applied.
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