Key Terms

back emf

emf generated by a running motor, because it consists of a coil turning in a magnetic field; it opposes the voltage powering the motor

eddy current

current loop in a conductor caused by motional emf

electric generator

device for converting mechanical work into electric energy; it induces an emf by rotating a coil in a magnetic field

Faraday’s law

induced emf is created in a closed loop due to a change in magnetic flux through the loop

induced electric field

created based on the changing magnetic flux with time

induced emf

short-lived voltage generated by a conductor or coil moving in a magnetic field

Lenz’s law

direction of an induced emf opposes the change in magnetic flux that produced it; this is the negative sign in Faraday’s law

magnetic damping

drag produced by eddy currents

magnetic flux

measurement of the amount of magnetic field lines through a given area

motionally induced emf

voltage produced by the movement of a conducting wire in a magnetic field

peak emf

maximum emf produced by a generator