An $LC$ tank circuit consists of an ideal capacitor $C$ connected in parallel with a coil of inductance $L$ having an internal resistance $R.$ The resonant frequency of the tank circuit is
- $\dfrac{1}{2\pi \sqrt{LC}}$
- $\dfrac{1}{2\pi \sqrt{LC}}\sqrt{1-R^{2}\dfrac{C}{L}}$
- $\dfrac{1}{2\pi \sqrt{LC}}\sqrt{1- \dfrac{L}{R^{2}C}}$
- $\dfrac{1}{2\pi \sqrt{LC}}\left(1-R^{2}\dfrac{C}{L}\right)$