the motor effect

• 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 causing the magnet and the conductor to exert a force on each other, this is called the motor effect
• to experience a full force, the wire has to be at 90 degrees to the magnetic field. if the wire runs parallel to the magnetic field it won't experience a force at all
• the force always acts at right angles to the magnetic field of the magnets and the direction of the current in the wire. to show direction of force, apply a current to a set of rains inside a horseshoe magnet. a bar is placed in the rails which completes the circuit. this generates a force that rolls the bar along the rails
• the magnitude of the force increases with the strength of the magnetic field. force increases with the amount of current passing through the conductor and the number of turns in the coil. also by increasing length of wire
• the force acting on a conductor in a magnetic field depends on

  the magnetic flux density - how many field lines

  the size of the current through the conductor

  the length of the conductor that in the magnetic field
• force = magnetic flux density x current x length
• you can find the direction of the force using Fleming's hand rule

  1. Using your left hand, point your first finger in direction of field.
  2. point second finger at direction of current
  3. your thumb will then point to direction of force
• if current or magnetic field, by flipping the magnet, is reversed, direction of force will be reversed.
• a motor converts electrical energy into mechanical energy - this is the opposite for a generator