An alpha particle (a helium nucleus) is lying at rest, att =0 an electric field given by e = 31+ 2) + 5k (n/c) applied on the particle for 5s then the electric field vanished; later on magnetic field given by b = (t + 5) + (3t+ -t) (mt) applied on the particle for 50 s. att - 8 s (take two when the magnetic field applied) find (a) the particle's speed, (b) the radius of the circle for the alpha particle trajectory, and (c) the period of the motion?