Question 49: AC fundamentals

Question

For the same resonant frequency, if L is changed from L to ${L \over 3}$, then capacitance should change from C to

Accepted Answer

The resonant frequency of a LC circuit is given by
$f = {1 \over {2\pi \sqrt {LC} }}$
when $L' = {L \over 3}$, as per question,
$f' = f \Rightarrow {1 \over {2\pi \sqrt {L'C'} }} = {1 \over {2\pi \sqrt {LC} }}$
$ \Rightarrow LC = L'C' \Rightarrow C' = {{LC} \over {L'}} = {{LC} \over {L/3}} = 3C$

Answer

${C \over 3}$

Answer

$3C$

Answer

${2 \over 3}C$

Answer

$2C$

AC fundamentals

For the same resonant frequency, if L is changed from L to {L \over 3}, then capacitance should change from C to

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