In a series LCR resonant circuit, the quality factor is measured as 100 . If
the inductance is increased by two fold and resistance is decreased by two
fold, then the quality factor after this change will be (round off to nearest integer)
(283)
Quality factor $=\frac{X_{\mathrm{L}}}{\mathrm{R}}=\frac{\omega \mathrm{L}}{\mathrm{R}}$
$\mathrm{Q}=\frac{1}{\sqrt{\mathrm{LC}}} \frac{\mathrm{L}}{\mathrm{R}}$
$\mathrm{Q}=\left(\frac{1}{\sqrt{\mathrm{C}}}\right) \frac{\sqrt{\mathrm{L}}}{\mathrm{R}}$
$\mathrm{Q}=\frac{\mathrm{XL}}{\mathrm{R}}=\frac{\omega \mathrm{L}}{\mathrm{R}}=\frac{1}{\sqrt{\mathrm{LC}}} \frac{\mathrm{L}}{\mathrm{R}}=\frac{1}{\mathrm{R}} \frac{\sqrt{\mathrm{L}}}{\sqrt{\mathrm{C}}}$
$\mathrm{Q}^{\prime}=\frac{\sqrt{2 \mathrm{~L}}}{\left(\frac{\mathrm{R}}{2}\right)^{\sqrt{\mathrm{C}}}}=2 \sqrt{2} \mathrm{Q}$
$\mathrm{Q}^{\prime}=282.84$