University Physics Volume 2

# 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
$μ0,μ0,$ 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