SSC JE Electrical Engineering 2012 Paper

Bandwidth is defined as the frequencies which power in the circuit is half of its maximum value.
Bandwidth of series RLC circuitBandwith $=\left({\mathit{f}}_2-{\mathit{f}}_1\right)=\frac{\mathit{R}}{2}\mathit{\pi }\mathit{L}$
where ${\mathit{f}}_1$ is called lower half frequency ${\mathit{f}}_2$ is called as upper half frequency.