Q 12-07-026NEETJEE MainMedium
In an LC circuit, the capacitor is initially charged. The energy is entirely magnetic after a time (period of oscillation $T$)
Answer: (A) $\dfrac{T}{4}$
The charge on C varies as $q_0\cos\omega t$. It first becomes zero (all energy in the inductor) at $\omega t = \dfrac{\pi}{2}$, i.e. $t = \dfrac{T}{4}$.
Solution by Sreeraj P, M.Sc Physics