Magnetism and electromagnetism

• What materials produce magnetic fields when nearby?

  Iron, cobalt, nickel
• What are the two types of forces that magnets can exert?

  Attractive and repulsive forces
• Where are the strongest magnetic forces found on a magnet?

  At the poles of the magnet
• What happens when like poles of magnets are brought together?

  They repel each other
• What is a magnetic field?

  Region around a magnet where force acts
• How do magnetic field lines behave around a magnet?

  Flow from the North pole to the South pole
• What does the density of magnetic field lines indicate?

  Strength of the magnetic field
• What does a magnetic compass contain?

  A small bar magnet
• Why does a compass needle point toward the North Magnetic pole?

  Because of Earth's magnetic field
• How can you investigate a magnetic field using a compass?

  Trace the direction of the field around a magnet
• What are the characteristics of permanent magnets?

  • Always magnetic
  • Produce their own magnetic field
  • Examples: Bar magnets, horseshoe magnets
• What are induced magnets?

  Temporary magnets that become magnetic in a field
• What happens to induced magnets when removed from a magnetic field?

  They quickly lose most of their magnetism
• What materials can become induced magnets?

  Iron and steel
• How do magnetic forces between poles occur?

  Due to the interaction of magnetic fields
• What direction do magnetic field lines always point?

  From north to south
• Where are magnetic fields strongest?

  Near the poles of the magnet
• Why does a compass always point North?


  Because of the magnetic in the compass
• What is electromagnetism?

  Interaction of electrical and magnetic fields
• How is a magnetic field created around a wire?

  When an electric current flows through it
• What shape do the magnetic field lines around a wire take?

  Concentric circles around the wire
• What does the Right-Hand Rule help determine?

  The direction of the magnetic field
• What factors affect magnetic field strength?

  Current and distance from the magnet
• What is a solenoid?

  A coil of wire producing a magnetic field
• How does the magnetic field of a solenoid compare to a bar magnet?

  It resembles that of a bar magnet
• What happens to the magnetic field inside a solenoid?

  It is uniform, very strong, and points in one direction
• How can you increase the strength of a magnetic field in a solenoid?

  Increase the current or add an iron core
• What is an electromagnet?

  A solenoid with an iron core
• What are some uses of electromagnets?

  Cranes and switches
• examples of permanent magnets:

  • bar magnets
  • horseshoe magnets
• permanent magnets always produce their own magnetic field and are always magnetic
• induced magnet are temporary magnets that becomes magnetic when placed in a magnetic field.
• induced magnets quickly lose all their magnetism when removed from their field.
• What happens when a current flows through a conducting wire?

  A magnetic field is produced around the wire
• How can you prove the existence of a magnetic field around a wire?

  By using a compass
• What does the compass needle do when the current is turned on?

  It deflects, indicating a magnetic field
• What factor affects the strength of the magnetic field around a wire?

  The size of the current
• How does the strength of the magnetic field change with distance from the wire?

  It decreases as we move further away
• What happens to the magnetic field if the direction of the current is reversed?

  The direction of the magnetic field reverses
• What rule do we use to determine the direction of the magnetic field produced by a wire?

  The right hand grip rule