1. A bar magnet experiences a torque of magnitude 0.075 Nm when it is perpendicular to a 0.50 T external magnetic field. What is the strength of the bar magnet's on-axis magnetic field at a point 20 cm from the center of the magnet? 2. torque = mu*b*sin(theta), in this case just mu*B 3. I need help getting started on this one. In the above equation, B is the external B field, not B for the bar magnet, correct? Thus, with the information given, I can find mu = AI... is this on the right track? If so what next?