Listen to the full series on BBC Sounds. Charge is a property of a body which experiences a force in an electric field. Charge is measured in coulombs (C). Since electrons are so small and one ...

Quantum field ... The Dirac equation had a sting in its tail: it predicted the existence of a particle identical to the electron in every way, apart from the opposite electric charge.

The energy of light is associated with its intensity and is proportional to the square of the amplitude of the electric field ... where the energy of an electron of charge e in the field of time ...