11 E An alpha particle can be produced in certain radioactive decays of nuclei and consists of two protons and two neutrons. The particle has a charge of q = +2.9 and a mass of 4.00 n, where u is the atomic mass unit, with l u = 1.661 X 1027 kg. Suppose an alpha particle travels in a circular path of radius 4.50 cm in a uniform magnetic field with B = 1.20 T. Calculate [aJIits speed, [b] its period of revolution, [c] its kinetic energy, and [d] the potential difference through which it would have to be accelerated to achieve this energy