A particle with unknown mass and charge is projected into the apparatus shown above. The particle moves with constant speed v as it passes undeflected through a pair of parallel plates, as shown. The plates are separated by a distance d, and a constant potential difference V is maintained between them. A uniform magnetic field of magnitude B directed into the page exists both in the region between the plates and in the region to the right of the plates that is enclosed by the dashed lines. In the region to the right of the plates, the particle's path is circular with radius r. Assume the effects of gravity are negligible compared to other forces.A) Explain why the particle moves through the parallel plates undeflected in terms of the forces exerted on the particle. B) What is the sign of the charge on the particle?