If the load driven by an alternator is purely ____________, what state is the current in relation to the potential difference?

When the load driven by an alternator is purely resistive, the current and the potential difference (voltage) are in phase with each other. This means that the peaks of the current wave align perfectly with the peaks of the voltage wave, creating a situation where the phase difference between them is zero degrees. In a purely resistive circuit, all the energy supplied by the voltage source is converted into heat, light, or other forms of energy without any reactive components introducing delays or phase shifts.

This behavior contrasts with inductive or capacitive loads, where either the current lags behind the voltage (in inductive circuits) or the current leads the voltage (in capacitive circuits). Reactive loads introduce phase differences due to their energy storage elements (inductors or capacitors), which complicate the relationship between voltage and current. Therefore, the characteristic of a purely resistive load is that current and voltage are always synchronized, resulting in efficient energy transfer without any phase shift.