A metal detector consists of a battery providing an alternating current to a transmitter coil and a receiver coil connected to a loudspeaker. Using Faraday's Law of Induction explain how a metal detector works. (5 marks)
The alternating current flows through the transmitted coil and produces a magnetic field around the coil. (1 mark) When the detector passes over a magnetic object, the magnetic field passes through the object. (1 mark) This creates a current around the object. (1 mark) This current induces another magnetic field opposing that of the transmitter coil, due to Lenz's Law. (1 mark) This magnetic field passes through the reciever coil, and as a result makes an electric current flow through the reciever coil and up to the loudspeaker. (1 mark)
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