In the case of an R.C series circuitser

Explanation

Capacitive Reactance:In an AC circuit, a capacitor offers opposition to current flow through the property of capacitive reactance (XC), measured in ohms (Ω). It is given by:XC = 1 / (2πfC)where:f: frequency (Hz)C: capacitance (F)Phase Difference in RC Circuit:The current (I) in an RC circuit leads the voltage (V) by a phase angle (φ) given by:φ = -tan⁻¹(XC / R)A negative sign indicates the current leading the voltage.R: resistance (Ω)Reasoning:In a capacitor, the current leads the voltage by 90 degrees (π/2) because the charging and discharging processes of the capacitor are not in sync with the voltage across it.As the voltage across the capacitor increases, the current initially rises to charge the plates. However, as the capacitor gets charged, the current starts decreasing even though the voltage continues to rise. This creates a phase shift between the voltage and current waveforms.Therefore, in an RC series circuit, the current leads the voltage by π/2