*poles of an electromagnet

• How to find out which pole is which in

  1. use a magnetic compass which points along magnetic field lines, so will point towards the south pole
  2. use a bar magnet with known poles. opposite poles attract and like poles repel so, bringing the bar magnet close to the electromagnet, you can detect which pole is which
• How to reverse the poles of an electromagnet

  1. wrap the coil around in the opposite direction
  2. reverse the connections on the cell or power supply