The circuit element where the impressed voltage is always in phase with the resulting current is

In an alternating current (AC) circuit, the phase relationship between voltage and current depends on the nature of the circuit elements. In a purely resistive circuit, such as one containing an ideal resistor, the current is directly proportional to the voltage according to Ohm's Law [t3][t9]. Consequently, the voltage and current are in phase, meaning they reach their maximum and minimum values simultaneously and their phasors are aligned [t7][t8]. In contrast, reactive elements introduce a phase shift: in an ideal inductor (coil), the voltage leads the current by 90 degrees (ELI), while in an ideal capacitor, the current leads the voltage by 90 degrees (ICE) [t1][t6]. An ideal transformer, being inductive in nature, also involves phase shifts or inversions depending on the winding configuration [t3]. Therefore, only the ideal resistor maintains a zero-degree phase difference between the impressed voltage and the resulting current.