Magnetism

An \(\alpha\)-particle (mass 4 amu) and a singly charged sulphur ion (mass 32 amu) are initially at rest. They are accelerated through a potential V and then allowed to pass into a region of uniform magnetic field which is normal to the velocities of the particles. Within this region, the \(\alpha\)-particle and the sulfur ion move in circular orbits of radii r_\(\alpha\) and r_s, respectively. The ratio (r_s/r_\(\alpha\)) is __________.