n the figure, an electron accelerated from rest through potential difference v$1=0\mathrm{.}855$kV enters the gap between two parallel plates having separation d$=16\mathrm{.}1$ mm and potential difference v$2=120$V$.$ The lower plate is at the lower potential. neglect fringing and assume that the electrons velocity vector is perpendicular to the electric field vector between the plates. In unit$-$vector notation, what uniform magnetic field allows the elctron to travel in a straight line in the gap. Number $($

k$)$ Units