Magnetic force (${\mathbf{F}}_B=q\mathbf{v}\times \mathbf{B}$)

The magnetic contribution to the Lorentz force on a point charge. It is perpendicular to that charge's instantaneous velocity, so its direct work on the charge is zero. Summing contributions in a conductor leads to the magnetic force on a current-carrying wire; mechanical work in moving circuits must also account for the electric fields and constraints that maintain the current.