1. a proton is first accelerated from rest through a potential difference v and then enters a uniform 0.750-t magnetic field oriented perpendicular to its path. in this field, the proton follows a circular arc having a radius of curvature of 1.84 cm. what was the potential difference δv? sketch the situation and start newton’s second law and conservation of energy to derive the equations you use to solve the problem. (mproton = 1.67 × 10-27 kg)