An electron of mass M kg and charge e coulomb travels from rest through a potential difference of V volts. The final energy in joules would be

Correct answer: (a) eV

Explanation

Work done on a charge by a potential difference is W = qV; here q = e, giving energy = eV joules.

Starting from rest, all this work becomes kinetic energy, so the final energy is eV.

The mass M affects the final speed but not the energy gained.