1. The problem statement, all variables and given/known data A particular ideal solenoid has 1200 turns/m, a radius of 10 cm, and a current of 4.0 A. An electron is fired from the axis of the solenoid in a direction perpendicular to the axis. What is the maximum speed the electron can have if it is not run into the side of the solenoid? I know the answer is 5.3 ×10^7 m/s but I have no idea how to arrive there... Any help would be great. Thanks. 2. Relevant equations u=4pi*10^-7 T m/A n=N/L B=u*n*I 3. The attempt at a solution I just plugged in the values to get B which ended up being .006032T and than used r=(mv)/(qB) to get v.... but that didn't seem to work.