1. The problem statement, all variables and given/known data Show that the force on a moving charged particle F = qv × B from a magnetic ﬁeld pointing perpendicular to the velocity produces a centripetal force and that this is equivalent to the equation pc = ABρ, where B is the magnetic ﬁeld strength (in Tesla) and ρ is the radius of the circular orbit (in meters). If we express p in GeV/c, what is the value of the constant A (which has units GeV/T-m) for a proton? 2. Relevant equations 3. The attempt at a solution I had no trouble with the first part of the problem. Since v is perpendicular to B, I just used F=(mv^2)/r and then multiplied both sides by c to get pc = qcB(rho). Now I have A = qc = 1.6x10^-19 C x c, however this is my first time working with eV units and am a bit lost on how to go about converting 'charge*c' to GeV/T-m.