Electromagnetism

• When a current flows through a wire, a magnetic field is created around the wire. This field is made up of concentric circles perpendicular to the wire, with the wire in the centre.
• This can be seen by placing a compass near a wire which is carrying a current. As you move the compass, it will trace the direction of the magnetic field
• Changing the direction of the current changes the direction of the magnetic field
• You can use the right-hand thumb rule to work out which way it goes.

  
• The strength of the magnetic field produced changes with the current and the distance from the wire. The larger the current or smaller the distance, the stronger the field
• Uses of electromagnets

  • Can be used in cranes to attract and pick up things made from magnetic materials
  • Can be used to act as switches