When an AC voltage is applied to insulation, the charging current is in which phase with the applied voltage?

When an AC voltage is applied to insulation, the charging current is in-phase with the applied voltage. This means that the current reaches its peak value at the same time as the applied voltage does.

In the context of capacitive behavior, the insulation acts like a capacitor where the applied voltage causes the insulation to become charged and establishes an electric field. The charging current during this process flows during the same cycle as the voltage, aligning in such a way that they are at their peak values simultaneously.

This in-phase relationship is characteristic of ideal capacitive circuits, where the current produced due to a voltage source can be expressed as a function of the voltage applied. As the insulation charges, it essentially takes on a capacitive nature, resulting in the current and voltage being synchronously aligned.

Other options present different relationships between voltage and current: out-of-phase would imply a phase shift that does not occur under ideal conditions for charging insulation, delayed suggests a phase difference where current lags voltage, and divided does not conform to the definitions related to phase relationships in electrical circuits.