Magnetic Field

We can define a magnetic field in a way analogous to an electric field.

The magnetic field is a vector and points along the magnetic field lines.
We will use the letter for the magnetic field.
Magnetic fields exert forces on moving charges. This force is called the Lorentz force and is given by: = q · $\times$
where q is the charge of the particle, its velocity, and is the magnetic field. The "$\times$" designates a cross product of two vectors.
The Lorentz force is always perpendicular to and . You can find the direction via the right-hand rule. If points in the direction of the thumb, and points in the direction of the index finger, then the force is outward in the direction of the middle finger, as shown to the right.
The magnitude of is: F = q v B sin$\theta$
where $\theta$ is the angle between and .

The units of B can be deduced from Lorentz force:

[B] = [F] / ([q]·[v]) = N·s / C·m = Newton·second/Coulomb·meter
This unit also has a special name:
1 N·s / C·m = 1 T (Tesla)
in honor of Nikola Tesla (1856-1943)

Since 1 C/s = 1 A, this is sometimes written 1 T = 1 N/A·m