A changing magnetic field can induce a voltage in a conductor; When a coil of wire encounters a magnetic field, a voltage is induced in the coil that is (1) directly proportional to the number of turns of wire in the coil and (2) directly proportional to the rate of change of the magnetic field with respect to the coil; The voltage induced across a coil equals the number of turns in the coil times the rate of change of the magnetic flux