MP Board · Class 12 · Physics · Alternating CurrentWhat is electrical resonance in a series LCR circuit? Write the formula for resonant frequency.

Electrical resonance is a condition in a series LCR circuit where the inductive reactance ($X_L$) becomes equal to the capacitive reactance ($X_C$). At resonance, the total impedance of the circuit drops to its minimum value, which is equal to pure resistance ($Z = R$), and consequently, the current amplitude reaches its maximum value. The resonant frequency ($f_r$) is given by the formula $f_r = \frac{1}{2\pi \sqrt{LC}}$, where $L$ is the self-inductance and $C$ is the capacitance of the given series circuit.