Which condition causes the phase angle in an AC circuit to move closer to 90 degrees?

In an AC circuit, the phase angle describes the relationship between voltage and current waveforms. A phase angle closer to 90 degrees indicates that the circuit is behaving more like a pure capacitive circuit. Specifically, when the capacitive reactance is high, it means that the opposition to the flow of current due to capacitance is significant.

This high capacitive reactance causes the current to lead the voltage by a larger angle, approaching 90 degrees. In this state, the circuit primarily allows current to flow with less influence from resistance, resulting in a more capacitive behavior where voltage lags behind current. This is essential in understanding the reactive power in AC circuits, where energy is stored in the electric field of a capacitor and returned to the circuit.

High inductance, while also significantly affecting the phase angle, typically leads to current lagging behind voltage, moving the angle closer to 0 degrees, not 90 degrees. Conversely, high resistance doesn't contribute to a phase angle change in the way specified, and low resistance generally results in a phase angle closer to 0 degrees as well. Hence, high capacitive reactance is the condition that specifically causes the phase angle in an AC circuit to shift closer to 90 degrees.