This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Current in a series LCR circuit = I = V / Z

Z=\sqrt{R^2+(\omega L-\frac{1}{\omega C})^2}

So Z = impedance is minimum when  ω L = 1 / (ω C) 
   ie.,  ω = 1 /√ (L C)

When impedance is minimum, then the current is maximum and that situation is called resonance of the circuit.

So resonance happens, when the frequency of the AC voltage source in the series LCR circuit is equal to 1/√(LC).

1 5 1