Magnetic Fields (Cambridge International IGCSE Science)

Magnetic fields

Extended tier only

• A magnetic field is defined as:

A region in which a magnetic pole experiences a force

• The direction of a magnetic field at a point is defined as:

The direction of the force on the N pole of a magnet at that point

Magnetic field around a bar magnet

• A magnetic field is indicated by field lines drawn around a magnet

• Field lines always have an arrow indicating the direction of the field

  • The direction of the field lines shows the direction that the magnetic force experienced by the north pole would act
  • The field lines always go from a north pole to a south pole

• The magnetic field is strongest at the poles

  • Therefore, the magnetic field lines are closer together at the ends of the magnets

• The magnetic field becomes weaker as the distance from the magnet increases

  • Therefore, the magnetic field lines get further apart

Magnetic field around a bar magnet

The magnetic field around a bar magnet

Exam Hint You are not expected to draw any magnetic fields or field lines but you should know what they look like and what the lines mean.