Week 9: Alternating Current Circuits 335
adding theMaxwell Displacement Currentto Ampere’s (broken) Law.
When we do, we will discover an amazing thing: time varying electromagnetic fields satisfy the
wave equationand hencepropagate like a wave. Under some circumstances those waves formradio
waves, like the AM encoded carrier wave we have just studied. In others, however, those waves are
what we know aslight!