1. The problem statement, all variables and given/known data An electron of speed v enters a region of magnetic field B directed normally to its velocity and is deflected into a circular path. Find an expression for the number of revolutions per second the electron will make. If the electron is replaced by a proton, how does your answer change? 2. Relevant equations revolutions per second = angular velocity = v/r I also know, that the answer should be f=eB/2pi(m) F=eBv sin(theta), where e=charge of an electron 3. The attempt at a solution I figured, that one needs to replace v by 2(pi)r, which is angular velocity. So, ma=eB2(pi)r From then, I do not know how to go farther, please help with your suggestions or even solutions! Thank you before hand!