The force exerted on a charge in an electric field is given by
F = qE.

For a charge in a magnetic field is the magnitude of the force is F = qvB sin(q), and the direction of the force is given by the right-hand rule.

When both electric and magnetic fields influence a charge the net force is simply the vector sum of these. This net force is known as the Lorentz force:

F = qE + qv ´ B