What happens to circuit resistance when the IR drop is decreased?

When the IR drop decreases, the circuit resistance remains the same because the resistance of a circuit is primarily defined by the physical characteristics of the circuit components, such as the materials and the geometry of wires or resistors, which do not change just based on voltage drop measurements.

The IR drop, which is the product of the current (I) passing through a resistance (R) and the resistance itself (V=IR), can be affected by changes in current or voltage, but the inherent resistance of the circuit components does not change as a direct response to a decrease in IR drop alone.

In essence, the IR drop merely reflects how voltage is being utilized across the components of the circuit, while resistance remains a constant property of the physical materials in the circuit. Hence, when the IR drop decreases, it indicates a change in current or voltage, but the resistance itself is unchanged.