The behavior of the dilution factors for a spherical anomaly in the theory of induced polarization

In the theory of induced electrical polarization, a dilution factor, B, is a measure of the sensitivity of the apparent resistivity of an object to changes in the apparent resistivities of other objects. Intuitively, one would expect B to exhibit two characteristics: when measured far away from an object, B should be small; and when measured inside a large object, far away from all interfaces, B should be close to unity. Surprisingly, the second expectation is not always met. It is shown that actual behavior becomes clear on consideration of the action of charges within the object. It is demonstrated that the departure of the apparent resistivity from its DC value is dominated by the departure of the more resistive medium