In the figure, an electron accelerated from rest through potential difference V1=0.851 kV enters the gap between two parallel plates having separation d = 27.5 mm and potential difference V2= 72.8 V. The lower plate is at the lower potential. Neglect fringing and assume that the electron's velocity vector is perpendicular to the electric field vector between the plates. In unit-vector notation, what uniform magnetic field allows the electron to travel in a straight line in the gap?
