Three concentric metallic shells A, B and C of radii a, b and c (a < b < c) have surface charge densities +σ, –σ and +σ respectively as shown in the figure.
![](https://www.sarthaks.com/?qa=blob&qa_blobid=7138473645243817336)
If shells A and C are at the same potential, then obtain the relation between the radii a, b and c.