posted by Kelly .
An ionized helium atom has a mass of 6.6*10^-27kg and a speed of 4.4*10^5 m/s. The atom moves perpendicular to a 0.75-T magnetic field on a circular path of radius 0.012m. Determine whether the charge of the ionized helium atom is +e or +2e.
Can anyone please give me some ideas to do it? Thanks!