The figure below shows six concentric conducting spheres, A, B, C, D, E, and F having radii R, 2 R, 4 R, 6 R, 7 R, and 9 R, respectively. Spheres B and C are connected by a conducting wire, as are spheres D and E. Determine the equivalent capacitance of this system. I understand that spheres B and C are equipotentials, as are D and E. Accordingly, they will share their charges with one another. V = Ke*Q(1/a - 1/b) for a conducting sphere. I plug this into C = Q/V to get C = 1/ke(1/a - 1/b). My problem is figuring how to knit these radii together into this equation... I guess the spheres which are connected by wire will act as equipotentials, or a capacitor series, and will have equal and opposite charges. This leaves the innermost radius and the outermost to cancel out one another, perhaps... But I'm trying to find the equivalent capacitance of the system, and I haven't done that with a system of spheres before. In a circuit, Ceq is dependent on the type of connections (series/parallel), here I feel like I'm having to make a few too many assumptions. I will try solving for Caf, Cbc and Cde, from there I'll have to find Ceq for the total system. Any help would be much appreciated here !