The ink drops have a mass m = 1.00×10-11 kg each and leave the nozzle and travel horizontally toward the paper at velocity v = 23.0 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 = 1.55 cm, where there is a uniform vertical electric field with magnitude E = 7.55×104 N/C.
If a drop is to be deflected a distance d = 0.270 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.