Consider A, D and C to be the co-centric shells of metal . Their radii are a ,b and c respectively (a < b < c). Their surface charge densities are `sigma, -sigma` and `sigma` respectively. Calculate the electric potential on the surface of shell A.

Explanation

The electric potential on the surface of A = potential due to charge on A
+ potential due to charge on B
+ potential due to charge on C
`=(1)/(4piepsilon_(0)).(4pia^(2)sigma)/(a)-(1)/(4piepsilon_(0))(4pib^(2)sigma)/(b)+(1)/(4pi epsilon_(0))(4pic^(2)sigma)/(c)`
`= (sigma)/(in_(0))[a-b+c]`