In an RC parallel circuit, how are the currents through the resistor and capacitor characterized?

In an RC parallel circuit, the currents through the resistor and capacitor are characterized by their phase relationship rooted in the nature of resistive and reactive components. The correct answer indicates that the currents are less than 90° out of phase, with the current through the resistor leading.

In a parallel circuit, the voltage across each component is the same, and the current through the resistor (which is purely resistive) is directly in phase with the voltage. However, the current through the capacitor, which is reactive, lags the voltage by 90°. This relationship means that while the resistor current is at its maximum when the voltage peaks, the capacitor's current cannot reach its maximum until the voltage increases and then decreases, creating a phase difference.

This less than 90° phase difference occurs because the total current flowing in the circuit is the vector sum of the currents through the resistor and the capacitor. While the resistor current is at its peak at the same moment that the voltage is maximum, the capacitor current reaches its peak a quarter cycle later. Hence, the resultant phasor relationship shows that while the currents' peaks are not simultaneous, they do not have a complete 90° phase difference, resulting in them being characterized as less than 90°