Now, since the emf between two points 1 and 2 is the work done per unit
charge in taking it from 1 to 2, the existence of an emf implies the existence
of an electric field So, we can rephrase Faraday’s law of electromagnetic
induction by saying that a magnetic field, changing with time, gives rise
to an electric field Then, the fact that an electric field changing with
time gives rise to a magnetic field, is the symmetrical counterpart, and is
FIGURE 8 2 (a) The
electric and magnetic
fields E and B between
the capacitor plates, at
the point M