What is the approximate rate of change of resistance with illumination for a photoconducti...

What is the approximate rate of change of resistance with illumination for a photoconductive cell with the characteristics of Fig. for the ranges (a) 0.1 → 1 kΩ, (b) 1 → 10 kΩ, and (c) 10 → kΩ? (Note that this is a log scale.) Which region has the greatest rate of change in resistance with illumination?

FIG. Photoconductive cell-terminal characteristics.