Practice question

**Magnetic field lines** form continuous closed loops, direction given by tangent at point, density indicates field strength. Unlike electric field lines, magnetic lines never intersect because unique field direction exists at each point, and bar magnet possesses dipole moment m = N I A directed from south to north pole inside magnet. Magnetic field lines represent the direction of the magnetic field at each point. If they intersected, it would imply two different directions for the field at the same point, which is physically impossible. This uniqueness stems from the vector nature of the magnetic field and the absence of magnetic monopoles. Substituting values gives