The motion of an electron inside electric and magnetic fields is governed by
eV = \(\frac{1}{2}\)mv2 = eV; eE = ma and BeV =\(\frac{mv^2}{r}\) where the symbols have their usual meanings.
In all the three relations, e and m occur separately. Further, the value of a physical variable involved in any of these reactions can be found by substituting the value of e/m.