A magnetic field energy of \( 34\times10^{-6}\,\mathrm{J} \) is stored in an inductor of inductance 1.7 mH in a LC circuit. The current flowing in the inductor is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 0.2 A
The energy stored in the magnetic field of an inductor is \( U = \tfrac{1}{2}LI^{2} \).
\( \displaystyle I = \sqrt{\frac{2U}{L}} \)
\( \displaystyle L = 1.7\,\mathrm{mH} = 1.7\times10^{-3}\,\mathrm{H} \)
\( \displaystyle I = \sqrt{\frac{2\times34\times10^{-6}}{1.7\times10^{-3}}} = \sqrt{0.04} = 0.2\,\mathrm{A} \)