Q. In an ideal parallel circuit, the capacitor is charged by connecting it to a source which is then disconnected. The current in the circuit

 2268  215 AIIMSAIIMS 2003Alternating Current Report Error

Solution:

When capacitor is connected to a DC source and then disconnected, it gets charged and then it starts discharging through the inductor. When capacitor is fully charged to , the current in inductor is zero, at this instant an amount of energy is stored in electric field between the plates of the capacitor.
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When circuit is closed, the capacitor begins to discharge through the inductor causing current to flow. The energy or electric field between the capacitor plates has transferred to magnetic field
By Lenz's law the dying magnetic field induces an emf in the inductance in the same direction as current. Hence, L-C circuit sets up oscillations.

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