Magnetic Fields and Forces (AP Physics C: E&M) Glossary

$\oint\vec{B}\cdotd\vec{l}=\mu_0 I_{enc}$. Relates the circulation of $\vec{B}$ to enclosed current; most useful with high symmetry.

Gives the differential magnetic field $d\vec{B}$ produced by a current element $Id\vec{l}$ at a field point.

Circular motion of a charged particle in a uniform magnetic field with radius $r=mv/(qB)$.

CGS unit of magnetic field. $1\;T = 10^4\;G$.

A voltage develops perpendicular to both current and $\vec{B}$ in a conductor, allowing measurement of carrier sign and density.

The total electromagnetic force on a charge: $\vec{F}=q(\vec{E}+\vec{v}\times\vec{B})$.

$\vec{\mu}=NIA\hat{n}$. Characterizes the strength and orientation of a current loop in a magnetic field.

A vector field produced by moving charges or currents that exerts forces on other moving charges. SI unit: tesla (T).

The surface integral of $\vec{B}$ over an area. $\Phi_B=\int\vec{B}\cdotd\vec{A}$. SI unit: weber (Wb).

$\mu_0=4\pi\times10^{-7}\;T\cdotm/A$. Fundamental constant in magnetostatics.

Curl fingers of right hand in direction of current; thumb points along $\vec{B}$ (for solenoid) or use cross-product rule for forces.

A tightly wound helical coil carrying current. Produces a nearly uniform interior field $B=\mu_0 nI$.

SI unit of magnetic field. $1\;T = 1\;\frac{kg}{A\cdots^2}$.

A doughnut-shaped coil. The field inside is $B=\frac{\mu_0 NI}{2\pi r}$; zero outside.

SI unit of magnetic flux. $1\;Wb = 1\;T\cdotm^2$.