Question

In a series LCR circuit, the plot of $I_m$ vs $\omega$ is shown in the figure. The bandwidth of this plot will be then

• A. Zero
• B. $0.1rad{s}^{-1}$
• C. $0.2rad{s}^{-1}$
• D. $0.4rad{s}^{-1}$

Answer 1

Answer: (D)

$0.4rad{s}^{-1}$

Bandwidth is the frequency range at which the current amplitude is $\frac{1}{\sqrt{2}}$ times the magnitude of the current.

$I_m=\frac{1}{\sqrt{2}}{I}_{max}=0.7I_{max}.$

From figure,
Band width at this value is :

$\Delta \omega =1.2-0.8=0.4rad{s}^{-1}$