Electromagnetism

Electromagnetism is the link between electricity and magnetism. In this lesson you will explore how electric currents produce magnetic fields, how electromagnets work in more detail, and how these principles are applied in real-world devices. This covers AQA GCSE Physics specification 4.7.2.

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The Link Between Electricity and Magnetism

In 1820, Hans Christian Oersted discovered that a wire carrying an electric current deflected a nearby compass needle. This was the first evidence that electricity and magnetism are linked.

Key principle: Whenever an electric current flows, a magnetic field is produced around the conductor.

This is the basis of electromagnetism — using electric currents to create controllable magnetic fields.

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Magnetic Field Around a Single Flat Circular Coil

When current flows through a flat circular coil (a single loop of wire), the magnetic field pattern has these features:

• At the centre of the coil, the field lines are approximately straight and parallel — the field is roughly uniform near the centre.
• At the edges, the field lines curve outward.
• The overall pattern from a distance resembles the field of a short bar magnet.