Principles of Electromagnetic Induction

• What is electromagnetic induction?

  Induction of e.m.f when a conductor moves through a magnetic field
• What happens when a conductor cuts through magnetic field lines?

  It causes a change in magnetic flux (ΔΦ)
• What is the result of work done during electromagnetic induction?

  It transforms into electrical energy
• What occurs when a current is induced in a complete circuit?

  Electromagnetic induction takes place
• How is electromagnetic induction defined?

  Induction of e.m.f in a closed circuit due to changes in magnetic flux
• When can electromagnetic induction occur?

  When a conductor cuts through a magnetic field or the field direction changes
• What are two applications of electromagnetic induction?

  Electrical generators and transformers
• How can electromagnetic induction be demonstrated?

  • Using a magnet and a coil
  • Using a wire and two magnets
• What happens when a bar magnet is moved through a coil connected to a voltmeter?

  An e.m.f is induced

  
• What is the expected voltmeter reading when the bar magnet is not moving?

  Zero reading

  
• What occurs when the bar magnet is held still inside or outside the coil?

  No e.m.f is induced

  
• What happens when the bar magnet begins to move inside the coil?

  A reading appears on the voltmeter

  
• What induces an e.m.f within the coil when the bar magnet moves?

  Change in magnetic flux (ΔΦ)

  
• What happens when the bar magnet is taken back out of the coil?

  An e.m.f is induced in the opposite direction

  
• How does the direction of the current change when the magnet changes direction?

  The direction of the current changes
• What effect does increasing the speed of the magnet have on the induced e.m.f?

  It induces a higher magnitude e.m.f
• What happens to the rate of change of flux as the speed of the magnet increases?

  The rate of change of flux increases
• What is the relationship between the induced e.m.f and the change that produces it?

  It opposes the change that produces it
• When is an e.m.f induced in the coil?

  Only when the bar magnet is moving

  
• What factors increase the induced e.m.f in the coil?

  • Moving the magnet faster through the coil
  • Adding more turns to the coil
  • Increasing the strength of the bar magnet

  
• What happens when a long wire is moved between two magnets connected to a voltmeter?

  An e.m.f is induced in the wire

  
• What is the expected voltmeter reading when the wire is not moving?

  Zero reading
• What occurs when the wire is held still inside or outside the magnets?

  No e.m.f is induced

  
• What happens as the wire is moved through the magnets?

  An e.m.f is induced within the wire

  
• What induces an e.m.f when the wire moves through the magnetic field lines?

  Change in magnetic flux
• What happens when the wire is taken back out of the magnetic field?

  An e.m.f is induced in the opposite direction
• How does the direction of the current change when the wire changes direction?

  The direction of the current changes
• What factors increase the induced e.m.f in the wire?

  • Increasing the length of the wire
  • Moving the wire between the magnets faster
  • Increasing the strength of the magnets