Magnetism and Matter — Important Questions

Bismuth, Copper, Water, Lead

Diamagnetic materials have negative magnetic susceptibility and are weakly repelled by magnets. Bismuth, copper, water, and lead are diamagnetic. Iron is ferromagnetic and aluminum is paramagnetic.

Large positive magnetic susceptibility, Presence of magnetic domains, Strongly attracted to magnets, Lose magnetization at Curie temperature

Ferromagnetic materials have large positive susceptibility, contain magnetic domains, are strongly attracted to magnets, and lose their ferromagnetic properties at the Curie temperature. They are not repelled by magnets.

Zero

Gauss's law for magnetism states that the net magnetic flux through any closed surface is zero because magnetic monopoles do not exist. The number of field lines entering equals the number leaving.

τ = m × B

The torque on a magnetic dipole in a uniform magnetic field is given by the cross product τ = m × B. The magnitude is τ = mB sin θ, where θ is the angle between m and B.