Thu, 30 December 2010
When a magnet is moved in or out of a coil, a current is induced in the coil. The size of the induced current depends on how fast the magnet is moved. The direction of the induced current depends on the polarity of the magnet and on the direction in which the magnet moves (i.e. towards the coil or away from the coil). The size of the induced emf (voltage) across the two ends of the coil can be determined from Faraday’s law. The “polarity” of the induced emf can be determined from Lenz’s law.