You are working for the summer at a research laboratory. Your research director has devised a scheme for holding small charged particles at fixed positions. The scheme is shown in the figure below. ,4 l I I I I l I I I I I l "1.. -___.__._..L__._____ __T_______ p '1 (D An insulating cylinder of radius a and length L >> a is positively charged and carries a uniform volume charge density p. A very thin tunnel is drilled through a diameter of the cylinder and two small spheres with charge (.7 are placed in the tunnel. These spheres are represented by the blue dots in the figure. They find equilibrium positions at a distance of r on opposite sides of the axis of the cylinder. Your research director has had great success with this scheme. (a) Determine the specific value of r at which equilibrium exists. (Use the following as necessary: q and p.) \\'our answer cannot be understood or graded. More Information isi'\