The Motor Effect

• What happens when a current-carrying wire is put between magnetic poles?

  The magnetic field around the wire interacts with the magnetic field it has been placed in. This causes the magnet and conductor to exert a force on each other. This is called the motor effect and can cause the wire to move
• What does the force acting on a conductor in a magnetic field depend on?

  • magnetic flux density (how many field lines there are in a region)
  • the size of the current through the conductor
  • the length of the conductor that's in the magnetic field
• Equation linking force, magnetic flux density, current and length?

  F = BIL
• How does the wire have to be placed to experience a full force?

  At 90 degrees to the magnetic field because if the wire runs parallel to the magnetic field, it won't experience any force at all
• Strength of the force increases with the strength of the magnetic field
• Force increases with the amount of current passing through the conductor
• How can you find the direction of a force?

  Using Fleming's Left-Hand Rule

  • Thumb - direction of force
  • First Finger = Field
  • Second Finger = Current