k/A summary of the derivative, gradient, curl, and divergence.11.5 Induced electric fields
11.5.1 Faraday’s experiment
Nature is simple, but the simplicity may not become evident un-
til a hundred years after the discovery of some new piece of physics.
We’ve already seen, on page 620, that the time-varying magnetic
field in an inductor causes an electric field. This electric field isnot
created by charges. That argument, however, only seems clear with
hindsight. The discovery of this phenomenon of induced electric
fields — fields that are not due to charges — was a purely exper-
imental accomplishment by Michael Faraday (1791-1867), the son
of a blacksmith who had to struggle against the rigid class struc-
Section 11.5 Induced electric fields 711