Magnetic Fields

• What is meant by a magnetic field?

  A magnetic field is a region around a magnet where a force acts on another magnet or on a magnetic material.
• How can you plot the magnetic field pattern of a magnet?

  You can plot it by moving a compass around the magnet and marking the direction of the field lines.
• What are the two types of magnets mentioned?

  Permanent magnets and induced magnets.
• What is the difference between a permanent magnet and an induced magnet?

  A permanent magnet always has a magnetic field; an induced magnet only has a magnetic field when in a magnetic field.
• What are the four types of magnetic materials?

  • Iron
  • Steel (an alloy of iron)
  • Cobalt
  • Nickel
• How does the strength of a magnetic field change with distance from the magnet?

  The strength of the magnetic field decreases with increasing distance from the magnet.
• Where is the magnetic field strongest in a magnet?

  The magnetic field is strongest at the poles of the magnet.
• How can the direction of a magnetic field be determined?

  The direction can be determined using a compass.
• What does it indicate if a compass needle always points in the north-south direction?

  It indicates that the Earth has its own magnetic field.
• What is the source of the Earth's magnetic field?

  The Earth's magnetic field is due to the Earth's core.