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How does the right-hand rule show the direction of a magnetic field around a wire?

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Learn about magnetic fields and the levels of particles, atoms, crystals, and domains — magnet Magnetic fields and the levels of magnetism of particles, atoms, crystals, and domains.

To determine the direction of a magnetic field around a current-carrying wire, you can use a variation of the right-hand rule. If you point the thumb of your right hand in the direction of the electric current flowing through the wire, your curled fingers will point in the direction of the magnetic field lines circling the wire.1

It is important to distinguish this from other right-hand rules used in electromagnetism. For example, when dealing with a current loop, if you curl your fingers in the direction of the current, your extended thumb points in the direction of the magnetic dipole moment. Additionally, a different right-hand rule is used to determine the direction of the Lorentz force on a moving charge or a current-carrying wire in an external magnetic field, where the thumb represents the current, the fingers represent the magnetic field, and the force is directed perpendicular to the palm.12