A long coaxial cable carries a uniform volume charge density \rho on the inner cylinder (radius a), and a uniform surface charge density on the outer cylindrical shell (radius b). This surface charge is negative and is of just the right magnitude that the cable as a whole is electrically neutral.
1) Discover the electric field in each of the three regions: (i) inside the inner cylinder (s < a), (ii) among the cylinders (a< s < b), (iii) outside the cable (s>b)
2) Discover the potential dissimilarity \Delta V between the inner and outer cylindrical shell.