How emf is induced
Electromagnetic Induction and its Effects
To explain a phenomenon that happens due to Electromagnetic Induction, we can use an acronym CFILE to structure our answer.
C stands for cutting of flux or changing of flux linkage. This is necessary for electromagnetic induction to happen. When a wire is pulled through a magnetic field perpendicular to it, it is said to be cutting the field lines. When a magnet enters a coil of wires, we can say that the magnetic flux linkage is increasing.
F stands for Faraday's law, which states that the induced e.m.f. in a circuit is directly proportional to the rate of change of flux-linkage or to the rate of cutting of magnetic flux.
I stands for an induced current. However, do note that this is only possible if there is a closed circuit or a path for the current to flow.
L stands for Lenz's law, which states that the direction of the induced e.m.f. is such that it tends to oppose the flux change causing it, and does oppose it if induced current flows.
E stands for effect. This is really just stating how an induced current or Lenz's law causes the phenomenon in question.