In an ink-jet printer, drops of ink are given a certain amount of charge before they move between two large pa

In an ink-jet printer, drops of ink are given a certain amount of charge before they move between two large parallel plates. The purpose of the plates is to deflect the charges so that they are stopped by a gutter and do not reach the paper. This is shown in Figure 21-16. The plates are d = 1.5 cm long and have an electric field of E = 1.2 106 N/C between them. Drops with a mass m = 0.14 ng and a charge q = 1.0 10-16 C are moving horizontally at a speed v = 12 m/s parallel to the plates. What is the vertical displacement of the drops when they leave the plates? To answer this question, go through the following steps.





(a) What is the vertical force on the drops?


N


(b) What is their vertical acceleration?


m/s2


(c) How long are they between the plates?


s


(d) Given that acceleration and time, how far are they displaced?


mmIn an ink-jet printer, drops of ink are given a certain amount of charge before they move between two large pa
(a) F=Eq


E and q are already given





(b) F=ma


F was found in (a)


m is already given





(c) The answer is, however long it takes the particle to travel 1.5cm at a rate of v


i.e. v=d/t


where v,d are given and t can be solved for





(d) Use the formula x=x0+v0t+0.5at^2 where x0 and v0 are the initial VERTICAL displacement and velocity, which are both zero, of course. (Remember, (c) was talking about HORIZONTAL displacement.)


Vertical a and t were found in (b) and (c), so finding x is trivial