The ink drops have a mass m $=1\mathrm{.}00\backslash$times $1011$ kg each and leave the nozzle and travel horizontally toward the paper at velocity v $=18\mathrm{.}0$ m$/$s $.$ The drops pass through a charging unit that gives each drop a positive charge q by causing it to lose some electrons. The drops then pass between parallel deflecting plates of length D$0=2\mathrm{.}15$ cm $,$ where there is a uniform vertical electric field with magnitude E $=8\mathrm{.}25\backslash$times $104$ N$/$C $.($Figure $1)$

Part A

If a drop is to be deflected a distance d $=0\mathrm{.}250$ mm by the time it reaches the end of the deflection plate, what magnitude of charge q must be given to the drop? Assume that the density of the ink drop is $1000$ kg$/$m$3,$ and ignore the effects of gravity.