Please help with the problem with included diagram. Operation of an Inkjet Print
ID: 1637034 • Letter: P
Question
Please help with the problem with included diagram.
Operation of an Inkjet Printer. In an inkjet printer, letters are built up by squirting drops of ink at the paper from a rapidly moving nozzle. The ink drops, which have a mass of 1.4 x 10 grams each, leave the nozzle and travel toward the paper at 20 m/s, passing through a charging unit that gives each drop a positive charge q by removing some of the electrons from it. The drops then pass between paralle deflecting plates 2.0 cm long where there is a uniform vertical electric field with magnitude 8.0 x 10 N/C. If a drop is to be deflected 0.30 mm by the time it reaches the end of the deflection plates, what magnitude of charge must be given to the drop? 3.Explanation / Answer
m = 1.4 x 10^-8 ; Vx = 20 m/s ; d = 2 cm = 0.02 m ; s = 0.3 mm = 3 x 10^-4 m
The forces acting on the drop are:
Fx = ma ; Fy = qE
qE = m ay => ay = qE/m
The velocity is constant in x direction since ax = 0
d = Vx t => t = d/Vx = 0.02/20 = 1 x 10^-3 s
from eqn of motion,
S = ut + 1/2 at^2
S = 1/2 (q E/m) t^2
q = 2m S/ E t^2
q = 2 x 1.4 x 10^-8 kg x 3 x 10^-4 m/[8 x 10^4 x (10^-3)^2] = 1.05 x 10^-10 C
Hence, Q = 1.05 x 10^-10 C