Faraday's law is applicable to a closed circuit made of thin wire and states that:
The induced electromotive force (EMF) in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit.
In essence, when a magnet is moving through a solenoid, electricity is produced across the terminals of the coil.
His main discoveries include that of the Magnetic Field, Induction, Diamagnetism and Electrolysis.
The SI unit of Capacitance, the Farad, is named in his Honor.