Revision notes:

• What is a magnetic field?

  A region where magnets experience a force
• Where is the magnetic field strongest?

  At the poles of the magnet
• How does the distance between magnetic field lines relate to field strength?

  Closer lines indicate a stronger magnetic field
• What type of force exists between a magnet and magnetic material?

  The force is always attractive
• What are the two types of magnetic poles?

  Attractive and repulsive
• What do compasses indicate?

  The directions of magnetic fields
• Why do compasses always point north?

  Earth generates its own magnetic field
• What do permanent magnets do?

  Produce their own magnetic field
• What happens to induced magnets in a magnetic field?

  They turn into magnets
• What occurs when an induced magnet is removed from a magnetic field?

  It loses its magnetism
• What happens when a current flows through a wire?

  A magnetic field is created around the wire
• How does changing the direction of the current affect the magnetic field?

  It changes the direction of the magnetic field
• What is the right-hand thumb rule used for?

  To determine the direction of the magnetic field

  
• What happens to the magnetic field strength when the current increases?

  The magnetic field strength increases
• What is a solenoid?

  A coil of wire
• How can you increase the strength of a solenoid's magnetic field?

  By increasing the number of turns in the coil
• What effect does adding a block of iron have on a solenoid?

  It increases the field strength
• What happens to the magnetic field when the current stops flowing?

  The magnetic field disappears
• What is an electromagnet?

  A solenoid with an iron core
• What is the motor effect?

  Force between a wire and magnetic poles
• How does the angle of the wire affect the force experienced?

  It must be at 90 degrees to experience full force
• What factors affect the magnitude of the force on a conductor?

  Magnetic flux density, current, length of conductor
• How can you calculate the force on a conductor at 90 degrees to the magnetic field?

  Using the provided equation
• What does Fleming’s left-hand rule indicate?

  Direction of force when current or field is reversed

  
• What happens to a current-carrying coil in a magnetic field?

  It rotates due to forces acting on it
• What role does the split-ring commutator play in a motor?

  It swaps contacts every half turn
• How can the direction of the motor be reversed?

  By reversing the current or the field
• What can increase the speed of an electric motor?

  Increasing current, magnetic flux density, and turns
• How can you determine the direction of coil rotation?

  Using Fleming’s left-hand rule