The hemisphere 0 < r < a, 0 < < /2, is composed of homogeneous conducting

The hemisphere 0 < r < a, 0 < θ < π/2, is composed of homogeneous conducting material of conductivity σ. The flat side of the hemisphere rests on a perfectly conducting plane. Now, the material within the conical region 0 < θ < α, 0 < r < a is drilled out and replaced with material that is perfectly conducting. An air gap is maintained between the r = 0 tip of this new material and the plane. What resistance is measured between the two perfect conductors? Neglect fringing fields.