We have a hollow conductive sphere of material with a resistive force with internal radius and outer radius b. (a) find the Rab resistance between...

We have a hollow conductive sphere of material with a resistive force ρ with internal radius α and outer radius b. (a) find the Rab resistance between the inner and outer surface of the sphere. (b) If we apply a Vab potential difference between the inner and outer surface then we have a current of intensity I. Find an expression for the current density as a function of the radius.