The quality factor (Q) of any resonant or anti resonant circuit is a measure of frequency selectivity and it defined by the equation
\(Q=\frac{\omega_0W}{P}\)
Where W=maxm energy stored
P=average power loss (dissipated power)
ω0=resonant frequency
\(Q=2\pi\frac{Maximum\ energy\ stored\ per\ cycle}{Energy\ dissipated\ for\ cycle}\)