Electromagnets

• Electromagnets


  Magnets that can be switched on and off using electric currents
• How to make an electromagnet

  1. Wrap wire into a coil (solenoid)

  2. Magnetic field lines line up inside the solenoid

  3. Magnetic field inside the solenoid is strong and uniform

  4. Magnetic field outside the solenoid is like a bar magnet

  5. Adding an iron core increases the field strength
• Solenoid


  A coil of wire
• Electromagnet


  A solenoid with an iron core, whose magnetic field can be turned on and off with an electric current
• Uses of electromagnets


  • Cranes to pick up magnetic materials
  • Switches in circuits (e.g. electric motor starters)
• Electromagnets are useful because they can be quickly turned on and off, and can create varying forces