11. d QI Figure 4: Consider this charge arrangement Consider the charge arrangement shown in figure 4: two long lines of uniform charge, both of length L, where QI = 4 nC, (22 = 8 nC, d = 0.3 m, L = 400 m. Both lines are perpendicular to the y axis in the x-y plane. QI is along the x-axis. Find the point on the y-axis where the total electric field is equal to O, in terms of distance from QI. Use either the equation sue to a line of charge, kQ or the long-line approximation, (1) (2) (b) Which equation is most appropriate to use in this case? Explain why you can or cannot use the long-line approximation in this case.