1. The problem statement, all variables and given/known data A parallel plate has p.d. V with one end 0V and the other +V. B-field of strength B has direction along plates. An electron is released from rest at 0V plate. Show that if V is less than e(DB)2/(2m) the electron will not reach the other plate. 2. Relevant equations 3. The attempt at a solution At half-way inbetween the plates, the radius must be d/2 R = mv/Bq d/2 = m*√(2*e*0.5V/m) / (Bq) I end up with e(DB)2/(4m) instead..