WAEC Physics 2023 Paper

Concept:In a series RLC circuit at resonance, the inductive reactance equals the capacitive reactance.Hence, the magnitudes of the voltages across the inductor and the capacitor are equal.Explanation:The same current flows through all components in a series circuit.At resonance, $X_L = X_C$, so $V_L = V_C$ in magnitude.Given $V_R = 30\,\text{V}$ and $V_L = 40\,\text{V}$.Therefore, $V_C = V_L = 40\,\text{V}$.Answer:The voltage across the capacitor is $40\,\text{V}$, which is Option D.