Consider a capacitor consisting of two concentric spherical conducting shells sepa- rated by a dielectric of permittivity \epsi . The outer radius of the inner conductor is a and the inner radius of the outer conductor is b. a) Use Gauss’ law to derive an expression for D between the shells and use this expression to determine E and \Phi . Hence determine the capacitance of the system. [5,5,5,5] b) Use Laplace’s equation to derive an expression for \Phi between the shells and use this expression to determine D, E. Hence determine the capacitance of the system. [5,5,5,5]