. a proton is at rest at the plane boundary of a region containing a uniform vertical magnetic field. an alpha particle moving with velocity, v makes a head-on elastic collision with the proton. the mass of alpha particle is four times that of the proton. the charge of the alpha particle is twice that of the proton. immediately after the collision, both particles enter the region with the magnetic field. the alpha particle feels a magnetic force of 12 n while moving perpendicular to the direction of the magnetic field. find the magnetic force felt by the proton after the collision while moving perpendicular to the direction of the magnetic field?
