Inkjet printers can be described as either continuous or drop-on-demand. In a co
ID: 1874917 • Letter: I
Question
Inkjet printers can be described as either continuous or drop-on-demand. In a continuous inkjet printer, letters are built up by squirting drops of ink at the paper from a rapidly moving nozzle. You are part of an engineering group working on the design of such a printer. Each ink drop will have a mass of 1.6x10-8 g. The drops will leave the nozzle and travel toward the paper at 50 m/s, passing through a charging unit that gives each drop a positive charge q by removing some electrons from it. The drops will then pass between parallel deflecting plates, 2 cm long, where there is a uniform vertical electric field with magnitude 7.0xI04 N/C.Your team is working on the design of the charging unit that places the charge on the drops Part A If a drop is to be deflected 0.30 mm by the time it reaches the end of the deflection plates, what magnitude t be given to the drop? Express your answer with the appropriate units. Value Units W e rExplanation / Answer
(A) time taken to pass the plates,
t = (2 x 10^-2 m) / (50 m/s)
t = 4 x 10^-4 sec
perpendicular to the plates,
y = v0y t + a t^2 / 2
0.30 x 10^-3 = 0 + a(4 x 10^-4)^2 / 2
a = 3750 m/s^2
and a = Fe / m = q E / m
3750 = (q) (7 x 10^4) / (1.6 x 10^-11)
q = 857 x 10^-15 C Or 857 fC
(B) q = n e
n = (857 x 10^-15) / (1.6 x 10^-19)
n = 5.36 x 10^6 electrons
(C) t' = 2 t
and a' = a/(2^2)
and q = q/4 = 214.25 x 10^-15 C