A certain particle is sent into a uniform magnetic field, with the particle's velocity vector perpendicular to the direction of the field. The figure gives the period T of the particle's motion versus the inverse of the field magnitude B. The vertical axis scale is set by Ts= 34.5 ns, and the horizontal axis scale is set by Bs-1= 4.0 T-1. What is the ratio m/q of the particle's mass to the magnitude of its charge?