1. The problem statement, all variables and given/known data The neutron is a particle with zero charge. Nonetheless, it has a nonzero magnetic moment with z-component 9.66 * 10^-27 A*m^2. This can be explained by the internal structure of the neutron. A substantial body of evidence indicates that a neutron is composed of three fundamental particles called quarks: an "up" (u) quark, of charge +2e/3, and two "down" (d) quarks, each of charge - e/3. The combination of the three quarks produces a net charge of 2e/3-e/3-e/3=0. If the quarks are in motion, they can produce a nonzero magnetic moment. As a very simple model, suppose the u quark moves in a counterclockwise circular path and the d quarks move in a clockwise, circular path, all of radius r and all with the same speed v. Determine the current due to the circulation of the u quark. 2. Relevant equations I would imagine... qv x B = F, Il x B = F, IA x B = torque... 3. The attempt at a solution I'm at a complete loss. I'm not even sure how a current can be produced if there's no wire for there to be a current produced in.