Magnetic force
= Magnetic force
{title2=$\mathbf F_B=q\mathbf v\times\mathbf B$}
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.