A magnetic field is a physical field that describes the magnetic influence exerted on moving electric charges, electric currents, and magnetic materials. It is a vector field, meaning it has both magnitude and direction at every point in space around a magnetic source
. Magnetic fields are produced primarily by moving electric charges (electric currents) and the intrinsic magnetic moments of elementary particles such as electrons. For example, when electric current flows through a wire, it generates a magnetic field around it. Similarly, permanent magnets create magnetic fields due to the alignment of atomic magnetic moments within the material
. The magnetic field exerts a force on moving charges that is perpendicular to both the velocity of the charge and the direction of the magnetic field, which can cause charged particles to move in circular or helical paths. This force underlies many technologies such as electric motors and generators
. Magnetic fields can be visualized by field lines that emerge from the north pole of a magnet and enter the south pole, forming closed loops. The density of these lines indicates the strength of the magnetic field at a given location
. In summary, a magnetic field is an invisible force field created by magnets or moving electric charges, influencing other charges and magnetic materials in its vicinity
