Physics – 4.5.3 Magnetic effect of a current | e-Consult

The strength of the magnetic field around a straight wire carrying a current decreases as the distance from the wire increases.

The magnetic field lines form concentric circles around the wire. As the distance from the wire increases, these circles spread out, resulting in the same magnetic flux being distributed over a larger area. This means the magnetic field strength (which is directly proportional to the magnetic flux density) becomes weaker.