A straight current-carrying wire creates a magnetic field around it. When an electric current flows through a wire, it generates a circular magnetic field that encircles the wire. The direction of the magnetic field can be determined using the right-hand rule. If you grasp the wire with your right hand so that your thumb points in the direction of the current, your fingers will curl in the direction of the magnetic field.

This magnetic field is perpendicular to the wire and its strength decreases as you move farther away from the wire. The strength of the magnetic field depends on the current magnitude and inversely with the distance from the wire. For instance, if you double the current flowing through the wire, the magnetic field strength at a particular point also doubles.

To visualize the magnetic field due to a straight current-carrying wire, imagine placing a compass near the wire. The compass needle will align itself with the magnetic field lines around the wire, forming concentric circles.