An alpha particle (the nucleus of helium nucleus with charge+2e and mass 4.0u ( 1u = 1.66 x 10-27) moves in acircular orbit of radius R=12cm in a uniform magnetic field of0.25T. Where the magnetic field is perpendicular to the plane.
a) the speed of the alpha particle
b) the period of the circular motion
c) the direction of the rotation