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J.J. Thomson's cathode ray experiment

by jcortez91
Tags: cathode, experiment, thomson
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May6-12, 01:49 PM
P: 7
In Rohlf's Modern Physics textbook it reads: "The value of q/m for the electron determined by Thomson wan substantially smaller than the values of q/m determined by electrolysis, that is, q/m for the electron is much smaller than for ionized atoms. There were two extreme possibilities: (1) The electron charge is much smaller than the charge of an ionized atom, or (2) the electron mass is much smaller than the mass of an ionized atom (or both!) " (Rohlf 12).

Of course we know the mass to be much smaller but is the book description correct? It seems to me that m/q should be smaller for electrons, not q/m, because either the mass is smaller or the charge is larger. Could someone shed light on this?

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May6-12, 06:27 PM
Sci Advisor
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P: 9,877
Looks like Rohlf has it backwards - good catch.
The confusion may arise because some refer to m/q and some to q/m.
May6-12, 08:27 PM
P: 7
Okay thanks. It was bugging me.

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