Self-Induction

Sections 4.1 and 4.2 dealt with an emf induced by a changing EXTERNAL magnetic field or an external conductor's motion. This section turns to a different, equally important source of induced emf: a coil (or pair of coils) inducing an emf purely because of a change in ITS OWN current, called self-induction, or in a neighbouring coil, called mutual induction. The property that governs how strongly a coil resists a change in its own current -- inductance -- turns out to play exactly the same physical role in electric circuit …