12.5: Magnetism and Current-Carrying Wires

Describe the magnetic field produced by a current-carrying wire.

A current-carrying wire produces a magnetic field.

• The magnetic field vectors around a long, straight current-carrying wire are tangent to concentric circles centered on that wire. The field has no component toward, away from, or parallel to a long, straight current-carrying wire.

• The magnitude of the magnetic field at a point due to a long, straight current-carrying wire is proportional to the magnitude of the current in the wire and inversely proportional to the perpendicular distance from the central axis of the wire to the point.

• The direction of the magnetic field created by a current-carrying wire is determined with the right-hand rule.

• The magnetic field at a given location near two or more current-carrying wires can be determined using vector addition principles.

Describe the force exerted on moving charged objects by a current carrying wire.

A magnetic field may exert a force on a current-carrying wire.

• The magnitude of the force exerted by a magnetic field on a current-carrying wire is proportional to the current, the length of the portion of the wire within the magnetic field, and the magnitude of the magnetic field, and depends on the angle between the direction of the current in the wire and magnetic field vectors.

• The direction of the force exerted by the magnetic field on a current-carrying wire is determined by the right hand rule.

Electrical Circuits in Space: The Electrodynamics of the Tethered Satellite