1. The problem statement, all variables and given/known data A charged particle moves in a straight line through a particular region of space. Could there be a nonzero magnetic field in this region? In either case, include a sketch as well as prose in your justification. 2. Relevant equations 3. The attempt at a solution The force that a magnetic field exerts on a charged particle moving through it is given by F=qvB, sin theta = qvB where B is the component of the field perpendicular to the particle’s velocity. Since the particle moves in a straight line the magnetic force must be zero.