1. The problem statement, all variables and given/known data There are 2 concentric shells. The outer shell of radius a is given a charge, while inner shell of radius b is earthed. We need to find the capacitance of the system. 2. Relevant equations Delta V = - integral E.dl (for some funny reason, latex is not working here) C = [tex]Q/ V[/tex] 3. The attempt at a solution Both the shells are at the same potential. So, [tex]\Delta[/tex]V = 0 So, capacitance should be infinite. Where am I going wrong?