1. The problem statement, all variables and given/known data How would you find the period of a charged particle in an uniform electric and magnetic field? The charged particle has velocity that is perpendicular to the magnetic and electric field (which are directed in the x-axis). 2. Relevant equations F=q(E+vxB) 3. The attempt at a solution In the absence of an electric field, I see that the period is given by T=2pi(m/qB). Not sure how I can find it when an electric field is present.