1. The problem statement, all variables and given/known data A capacitor is formed of two concentric spherical conducting shells of radii r1 and r3. The space between the shells is filled from r1 to r2 with a dielectric of relative permittivity [tex]\epsilon[/tex]r1 and from r2 to r3 with a dielectric of relative permittivity [tex]\epsilon[/tex]r2. Derive an expression for the capacitance of this capacitor. 2. Relevant equations C = Q/V 3. The attempt at a solution I know that the dielectric reduces the E. But i seriously do not know where to start from.