Electromagnets

• What is the difference between bar magnets and electromagnets?

  Bar magnets stay magnetic all the time
• What happens when a current flows through a wire?

  A magnetic field forms around the wire
• What is a solenoid?

  A long coil of wire
• How does a solenoid's magnetic field compare to a bar magnet's field?

  It is the same when current flows
• What are magnets made from current-carrying wire called?

  ELECTROMAGNETS
• Why can the magnetic field of an electromagnet be turned on and off?

  Because the current can be turned on and off
• How can you increase the strength of an electromagnet?

  • Increase current in the wire
  • Add more turns on the solenoid
  • Use a soft iron core inside the solenoid
• What type of core is used for an electromagnet?

  Soft iron
• Why is soft iron preferred for electromagnet cores?

  It turns on and off with current
• What happens if a steel core is used in an electromagnet?

  It stays magnetized after current is off
• What are the main components of a simple electric motor?

  • Loop of coiled wire
  • Magnetic field
  • Current flowing through the wire
• What occurs when current flows through the wire in a motor?

  A magnetic field forms around the wire
• How do forces act on the loop of wire in a motor?

  They act in opposite directions
• What is the result of the forces acting on the loop of wire?

  It causes the loop to turn
• What are some applications of electromagnets?

  • Used in electric motors
  • Used in medicine
  • Used in scrap yards
  • Used in loudspeakers
• What should you know about electromagnets for the exam?

  How to strengthen one and how a motor works