The magnetic flux density in a conductor is directly proportional to the current flowing through it.

To elaborate, the relationship between magnetic flux density ($B$) and current ($I$) in a conductor is described by Ampere’s Law. This fundamental principle states that the magnetic field generated by an electric current is proportional to the magnitude of that current, with the constant of proportionality being the permeability of free space ($\mu_0$). The relationship can be expressed mathematically as:

In this equation, $B$ represents the magnetic flux density, $\mu_0$ is the permeability of free space, $I$ is the electric current, and $r$ is the distance from the wire.

The magnetic field surrounding a conductor carrying an electric current is always circular in shape. The direction of this magnetic field is determined by the right-hand grip rule. To apply this rule, grip the conductor with your right hand, ensuring your thumb points in the direction of the current. Your fingers will naturally curl around the conductor, indicating the direction of the magnetic field.