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Question
What is so special about the combination e/m? Why do we not simply talk of e and m separately?
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Solution
The basic relations for electric field and magnetic field are `("eV" = 1/2 "mv"^2)` and `("eBv" = ("mv"^2)/"r")` respectively
These relations include e (electric charge), v (velocity), m (mass), V (potential), r(radius), and B (magnetic field). These relations give the value of velocity of an electron as `["v" = sqrt(2"V"("e"/"m"))]` and `["v" = "Br"("e"/"m")]` respectively.
It can be observed from these relations that the dynamics of an electron are determined not by e and m separately, but by the ratio e/m.
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