Generating Voltage

The relative motion between a conductor and magnetic field is used to generate an electrical voltage

Students learn to:

• outline Michael Faraday’s discovery of the generation of an electric current by a moving magnet
• define magnetic field strength B as magnetic flux density
• describe the concept of magnetic flux in terms of magnetic flux density and surface area
• describe generated potential difference as the rate of change of magnetic flux through a circuit
• account for Lenz’s Law in terms of conservation of energy and relate it to the production of back emf in motors
• explain that, in electric motors, back emf opposes the supply emf
• explain the production of eddy currents in terms of Lenz’s Law

Students:

• perform an investigation to model the generation of an electric current by moving a magnet in a coil or a coil near a magnet
• plan, choose equipment or resources for, and perform a first-hand investigation to predict and verify the effect on a generated electric current when:
  • the distance between the coil and magnet is varied
  • the strength of the magnet is varied
  • the relative motion between the coil and the magnet is varied
• gather, analyse and present information to explain how induction is used in cooktops in electric ranges
• gather secondary information to identify how eddy currents have been utilised in electromagnetic braking