38.
R-L-C 직렬회로의 공진 주파수는?
①
\(\frac{1}{2\pi\sqrt{LC}}\)
②
\(\frac{2\pi}{\sqrt{LC}}\)
③
\(\sqrt{\frac{1}{LC}-\left(\frac{R}{2L}\right)^2}\)
④
\(\frac{1}{2\pi}\sqrt{\frac{1}{LC}-\left(\frac{R}{2L}\right)^2}\)