1. The problem statement, all variables and given/known data# Two long, concentric, conducting cylinders of radii and b (a<b) each carry a current I in opposite directions and maintain a potential difference V. An electron with velocity u (parallel to the cylinders) travels undeviated through the space between the two cylinders. Find an expression for |u| 2. Relevant equations F=q(E+u^B) 3. The attempt at a solution All I've managed is to say that there must be no net force, so E=-u^B E=-|u||B|sinθ I'm not sure how to work out the electric of magnetic field.