In Fig. 28.8, a view of the solenoid, showing the clockwise sense of the current in the windings, is given. An electron is in circular motion near the center of the solenoid, with an orbital diameter of 3.0 cm. The speed of the electron and the sense of the orbital motion are closest to The diameter of the solenoid is 4 cm The diameter of the e- orbiting within the solenoid is 3 cm 2. Relevant equations r = mv/qb T= (2*pi*m)/qb 3. The attempt at a solution Not really sure how to start the problem. Would I take a conservation of energy approach? Do I need to try and figure out the B field of the solenoid?