Đáp án:
\(\begin{array}{l}
3.\\
C = 1,{0132.10^{ - 4}}\\
5.\\
C = 5,{066.10^{ - 5}}\\
7.\\
f = \frac{{250000}}{\pi }
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
3.\\
\omega = \frac{1}{{\sqrt {LC} }}\\
1000\pi = \frac{1}{{\sqrt {{{10}^{ - 3}}C} }}\\
C = 1,{0132.10^{ - 4}}\\
5.\\
\omega = \frac{1}{{\sqrt {LC} }}\\
1000\pi = \frac{1}{{\sqrt {{{2.10}^{ - 3}}C} }}\\
C = 5,{066.10^{ - 5}}\\
7.\\
f = \frac{1}{{2\pi \sqrt {LC} }} = \frac{1}{{2\pi \sqrt {{{2.10}^{ - 3}}{{.2.10}^{ - 9}}} }} = \frac{{250000}}{\pi }
\end{array}\)
