A3. The Electric Field Operation of an Inkjet Printer 5 of 6 > The ink drops hav
ID: 1578815 • Letter: A
Question
A3. The Electric Field Operation of an Inkjet Printer 5 of 6 > The ink drops have a mass m = 1.00x10-11 kg each and leave the nozzle and travel horizontally toward the paper at velocity u = 22.0 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 Do-2.50 cm, where there is a uniform vertical electric field with magnitude E = 7.50×104 N/C-Figure 1) nstants In an inkjet printer, letters and images are created by squirting drops of ink horizontally at a sheet of paper from a rapidly moving nozzle. The pattern on the paper is controlled by an electrostatic valve that determines at each nozzle position whether ink is squirted onto the paper or not. Part A Figure 1 of 1> If a drop is to be deflected a distance d = 0.340 mm by the time it reaches the end of the deflection plate, what magnitude of charge must be given to the drop? Assume that the density of the ink drop is 1000 kg/m3, and ignore the effects of gravity. Express your answer numerically in coulombs Do View Available Hint(s) 9Explanation / Answer
electric force, Fe = q E upward
a = Fe / m = q E / m upward
in the direction of initial velocity there is no acceleration.
hence timetaken to cross the plates,.
t = D0 / V0 = (2.50 x 10^-2 m) / (22 m/s)
t =1.136 x 10^-3 sec
along Fe direction.
d = v0y t + ay t^2 /2
0.340 x 10^-3 = 0 + (q E / m) (1.136 x 10^-3)^2 /2
q E / m = 526.592
q = 70.2 x 10^-15 C