Practice question

**Lorentz force** on charge q moving with velocity v in magnetic field B is F = q v × B, magnitude F = q v B sinθ, θ angle between v and B (degrees), unit N. Direction perpendicular to both v and B via right-hand rule. When v ⊥ B, motion circular with radius r = m v/(q B), centripetal force provided by magnetic force. The direction of the magnetic field around a current-carrying straight wire is determined by the right-hand rule: grasp the wire with your right hand, thumb pointing in the direction of the current, and your fingers curl in the direction of