3. In figure (a) below, particle 1 of charge q, and particle 2 of charge q2 are fixed in place on the x axis a distance L apart. Particle 3 of charge q3 = Q > 0 is to be placed on the line between particles 1 and 2 so that they produce a net electrostatic force F3 on it. Figure (b) shows a plot of the x component Fax of force F3 versus the coordinate x at which particle 3 is placed. The scale of the x axis is set by Xs = L. V) X 0 + x (cm) F (10-23 (a) (b) (a) Write down an expression for the total force F3 acting on particle 3 in terms of the parameters q1, 92, 93, x, L, and i. (b) Find the sign of charge q1. (c) Find the ratio 92/91 including sign