Electromagnetism — Current-Carrying Conductors

When an electric current flows through a conductor, it produces a magnetic field around it. This discovery — that electricity and magnetism are linked — is called electromagnetism. This lesson covers the magnetic field around a straight wire and around a flat circular coil. It maps to AQA GCSE Combined Science Trilogy (8464) specification section 6.7.2 — The magnetic effect of a current.

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Magnetic Field Around a Straight Current-Carrying Wire

When a current flows through a straight wire, a magnetic field is produced around the wire.

Key Features

• The field lines are concentric circles centred on the wire.
• The field is strongest close to the wire (circles are closest together).
• The field gets weaker further from the wire (circles spread out).
• The direction of the field depends on the direction of the current.

graph TD
    subgraph "Field Around a Straight Wire — Top View"
        W["Wire (current flowing OUT of page ⊙)"] --> C1["Inner circle — strong field"]
        C1 --> C2["Middle circle"]
        C2 --> C3["Outer circle — weaker field"]
    end

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The Right-Hand Grip Rule (for a Wire)