Key Terms

Key Terms

Ampère’s law

physical law that states that the line integral of the magnetic field around an electric current is proportional to the current

Biot-Savart law

an equation giving the magnetic field at a point produced by a current-carrying wire

diamagnetic materials

their magnetic dipoles align oppositely to an applied magnetic field; when the field is removed, the material is unmagnetized

ferromagnetic materials

contain groups of dipoles, called domains, that align with the applied magnetic field; when this field is removed, the material is still magnetized

hysteresis

property of ferromagnets that is seen when a material’s magnetic field is examined versus the applied magnetic field; a loop is created resulting from sweeping the applied field forward and reverse

magnetic domains

groups of magnetic dipoles that are all aligned in the same direction and are coupled together quantum mechanically

magnetic susceptibility

ratio of the magnetic field in the material over the applied field at that time; positive susceptibilities are either paramagnetic or ferromagnetic (aligned with the field) and negative susceptibilities are diamagnetic (aligned oppositely with the field)

paramagnetic materials

their magnetic dipoles align partially in the same direction as the applied magnetic field; when this field is removed, the material is unmagnetized

permeability of free space

${\mu }_0,$ measure of the ability of a material, in this case free space, to support a magnetic field

solenoid

thin wire wound into a coil that produces a magnetic field when an electric current is passed through it

toroid

donut-shaped coil closely wound around that is one continuous wire