Electromagnets

• What can electric currents create?

  Magnetic fields
• What are electromagnets?

  Magnets that can be switched on and off
• What is a solenoid?

  • A coil of wire
  • Used to increase magnetic field strength
• How can you increase the strength of the magnetic field produced by a wire?

  By wrapping the wire into a coil
• Why do field lines around each loop of wire line up in a solenoid?

  To create a stronger magnetic field
• What happens to the field lines in a solenoid?

  They point in the same direction and are close
• What is the characteristic of the magnetic field inside a solenoid?

  It is strong and uniform
• How does the magnetic field outside a solenoid compare to a bar magnet?

  It is similar to that of a bar magnet
• What happens to the magnetic field when the current stops in a solenoid?

  The magnetic field disappears
• What is an electromagnet?

  A solenoid with an iron core
• How can the strength of an electromagnet be increased?

  By increasing the number of wire turns
• In what applications are electromagnets commonly used?

  Electric bells, car ignitions, security doors
• What factors affect the strength of an electromagnet?

  Number of wire turns and current size