Edit: The title is misleading because I initially was going to ask a different question. 1. The problem statement, all variables and given/known data A singly charged ion of mass m is accelerated from rest by a potential difference ΔV. It is then deflected by a uniform magnetic field (perpendicular to the ion's velocity) into a semicircle of radius R. Now a triply charged ion of mass m' is accelerated through the same potential difference and deflected by the same magnetic field into a semicircle of radius R' = 6R. What is the ratio of the masses of the ions? 2. Relevant equations W = qV L = mvr 3. The attempt at a solution I know that V stays the same in each instance, but I am not sure how exactly to relate the masses. Thanks for any help.