Magnetism and Matter

A bar magnet is fundamentally

A bar magnet is fundamentally a magnetic dipole with a north pole and a south pole. Unlike electric dipoles, magnetic poles cannot be isolated—cutting

Magnetic field lines form continuous closed

Magnetic field lines form continuous closed loops, unlike electric field lines which begin on positive charges and end on negative charges. Key proper

When a magnetic dipole with moment

When a magnetic dipole with moment m is placed in an external uniform magnetic field B, it experiences a torque τ = m × B = mB sin θ, where θ is the a

For a bar magnet of magnetic

For a bar magnet of magnetic moment m, at distances r >> l (where l is the magnet's length), the magnetic field resembles that of an electric dipole:

The net magnetic flux through any

The net magnetic flux through any closed surface is always zero: ∮ B·dS = 0. This fundamental law reflects the fact that magnetic monopoles do not exi