Question

The capacitance in an oscillatory LC circuit is increased by 1%. The change in inductance required to restore its frequency of oscillation is to

• A. decrease it by 0.5%
• B. increase it by 1%
• C. decrease it by 1%
• D. decrease it by 2%

Answer 1

Answer: (C)

decrease it by 1%

${\omega }_r=constant$
$\Rightarrow LC=constant$
$\Rightarrow LdC+CdL=0$
$\Rightarrow \frac{dL}{L}=-\frac{dC}{C}=-1$