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how did thomson show that cathode rays are different from light
In a series of experiments in the 1890's, J.J.Thompson showed that cathode rays, or electrons, are: deflected by an electric field, they are bent by a magnetic field, and that their charge to mass ratio is about 1/2000th of that of the proton. Light does not have any of these properties. Take a look at the Wikipedia article http://en.wikipedia.org/wiki/J._J._Thomson
(published on 10/22/2007)
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