Magnetism and Electromagnetism

• What are the two poles of a magnet?

  North and south pole
• What happens when a north pole is brought near a south pole?


  They attract each other
• What is the interaction between two south poles of magnets?


  They repel each other
• What type of force do magnetic materials experience when placed near a magnet?


  A non-contact force
• What are the three magnetic metals?


  Iron, nickel, and cobalt
• What is a magnetic field?


  An area where a magnetic material will experience a force
• What does a permanent magnet have?


  Its own magnetic field
• How do magnetic field lines behave around a magnet?


  They travel out of the north pole and into the south pole
• What does the spacing of magnetic field lines indicate?


  The strength of the magnetic field
• How can we determine the shape of a magnetic field?


  • Using plotting compasses
  • Using iron filings
• What does the Earth have that is similar to a magnet?


  Its own magnetic field
• How does the Earth's magnetic field assist in navigation?


  It allows compasses to work
• What does an electromagnet do in an electric bell?


  It attracts the iron armature
• What happens when the iron armature moves in an electric bell?


  It breaks the circuit
• What occurs after the circuit is broken in an electric bell?


  The coil and core are no longer magnetic
• What happens when the spring returns to its original position in an electric bell?


  The bell is rung once
• How does a circuit breaker function?


  It detects large changes in current and breaks the circuit
• What happens when a large current flows in a circuit breaker?

  The electromagnet attracts an iron catch to break the circuit
• Can circuit breakers be reset after they break a circuit?


  Yes, they can be reset and used again
• What is the purpose of circuit breakers in homes?


  They serve as an electrical safety device
• How do loudspeakers generate sound?


  By using an electromagnet to move a cone in and out
• What creates the electromagnet in a loudspeaker?


  A current passing through the coil
• What happens when the electromagnet in a loudspeaker repels another magnet?


  It moves the cone, creating sound
• How are electromagnets constructed?


  • By wrapping a coil of wire around a magnetic core
  • They only work when electricity flows through the coil
• How do electromagnets compare to permanent magnets in strength?


  Electromagnets are stronger than permanent magnets
• What shape does the magnetic field of an electromagnet produce?


  The same shape as a bar magnet
• How can the strength of an electromagnet be increased?


  • Increase the number of turns on the coil
  • Increase the current flowing through the coil
  • Use a more magnetic material for the core (e.g., iron)
• What are the key terms related to electromagnets and magnets?

  • Attract
  • Core
  • Circuit breaker
  • Electromagnet
  • Electric bell
  • Loudspeaker
  • Magnet
  • Magnetic pole
  • Magnetic field lines
  • Magnetic material
  • Permanent magnet
  • Repel