Final answer:
Reducing the absolute value of a battery's potential difference leads to a decrease in the potential energy change and the overall power delivered because the driving force for electron movement declines, but the number of electrons at both terminals remains equal.
Step-by-step explanation:
When the absolute value of the potential difference across a battery is reduced, this indicates that the driving force behind the electron movement declines. As per the information provided, we know that a battery moves electrons from the negative terminal to the positive terminal. If we decrease the voltage, the potential energy change, given by the formula ΔPE = qΔV (where q is the charge and ΔV is the potential difference), will also decrease. This is because the charge (q) remains constant, and the flow of electrons continues at a reduced rate due to the lower potential difference. Consequently, the battery will supply less energy to the circuit per electron, leading to a decrease in the overall power delivered. The number of electrons remains equal at both the negative and positive terminals, obeying the principle of charge conservation.