Electricity: Magnetism and Electromagnets

• Give the names of four metals that are magnetic?

  Steel, Cobalt, Nickel and Iron
• What type of force is magnetism?

  A non-contact force
• What is a magnetic field?


  It's an area around a permanent magnet where a magnetic force has an effect
• Which parts of a bar magnet have the strongest magnetic field?

  The ends of the magnet as that is where the field lines are closer together
• What happens when two like poles of a bar magnet are brought close to each other?

  They repel each other
• What happens when two opposite poles of a bar magnet are brought close to each other?


  They are attracted to each other
• Why does a compass always point north?


  Because the needle always follows the Earth's magnetic field, which goes south to north
• State 2 ways that the Earth's magnetic field can be useful?


  1. Allows compasses to be used
  2. Protect Earth from solar radiation
• What equipment would you need to make an electromagnet?


  A piece of magnetic material and an exposed wire
• How does an electromagnet differ from a permanent magnet?


  An electromagnet can be turned on and of
• What is a solenoid?


  A solenoid is a coil of wire that generates a magnetic field when a electric current is run through it
• State 3 ways that the strength of an electromagnet can be increased?


  1. More coils
  2. Higher current
  3. Add an iron core
• Why should a steel core not be used to make an electromagnet?


  Because when steel is put inside a magnetic field, it becomes a permanent magnet. This means that the electromagnet cannot be turned off
• List 3 everyday uses of electromagnets?

  1. In an alarm clock
  2. In electric cars
  3. In electric fans
• Define the term "attract" in relation to magnetism?

  When two objects are attracted together by magnetism
• Define the term "repel" in relation to magnetism?


  When objects repel away from each other due to magnetism
• Describe the method used to plot the magnetic field pattern around a bar magnet using a compass?

  You slowly move the compass along following where the needle points