Two perfectly conducting spherical shells have radii a = 3 cm and b = 6 cm. The region between the two shells is filled with a dielectric with relative permittivity of 9. The inner sphere is at voltage 10 V while the outer sphere is at 0 V. Find the electric filed strength in V/m at the surface of the inner spherical shell i.e. at r = a.

Two perfectly conducting spherical shells have radii a = 3 cm and b = 6 cm. The region between the two shells is filled with a dielectric with relative permittivity of 9. The inner sphere is at voltage 10 V while the outer sphere is at 0 V. Find the electric filed strength in V/m at the surface of the inner spherical shell i.e. at r = a.