전자기학
전자기학
자기에너지
2003.3 기출
\(\ell=100\)cm, \(S=10\)cm², \(\mu_s=100\), \(N=1000\)회 자기회로에 \(I=10\)A를 흘릴 때 저장에너지[J]는?
- ① \(2\pi\times10^{-1}\)
- ② \(2\pi\times10^{-2}\)
- ③ \(2\pi\times10^{-3}\)
- ④ \(2\pi\) 정답
📖 해설
\(W=\tfrac12LI^2\), \(L=\dfrac{\mu_0\mu_sSN^2}{\ell}\)
\(L=\dfrac{4\pi\times10^{-7}\times100\times10\times10^{-4}\times1000^2}{1}=4\pi\times10^{-2}\)H.
\(W=\tfrac12\times4\pi\times10^{-2}\times10^2=2\pi\)[J].
\(L=\dfrac{4\pi\times10^{-7}\times100\times10\times10^{-4}\times1000^2}{1}=4\pi\times10^{-2}\)H.
\(W=\tfrac12\times4\pi\times10^{-2}\times10^2=2\pi\)[J].