Question

In an oscillating system, a restoring force is a must. In an L-C circuit, restoring force is provided by
A. Capacitor
B. Inductance
C. Resistance
D. Both (A) and (B)

Answer 1

Hint: An L-C circuit is the circuit consisting of an inductor represented by L and a capacitor represented by C. An L-C circuit is a model in which there is no dissipation of energy even if there is no resistance in the circuit. it is used to provide the positive feedback for sustaining the oscillations.

Complete answer:
When an inductor is connected to a charged capacitor, then the electric current and the charge on the capacitor in the circuit will lead to LC oscillation.
Now, in the oscillating circuit, the total energy in the circuit is always constant as the charge on the capacitor and the current on the inductor is oscillating.
Now, when the current in the circuit reaches its maximum value, the charge on the capacitor will become zero and all the energy will be stored in the inductor. When the current in the circuit starts decreasing, the charge on the capacitor will go on increasing. Hence, in this case, the restoring force is provided by the inductor.
Now, when the charge reaches its maximum value, then the current in the circuit will become zero and all the energy will be stored in the capacitor. When the current in the circuit starts increasing, the charge on the capacitor will start decreasing. Hence, in this case, the restoring force is provided by the capacitor.
Hence, in an L-C circuit, the restoring force is provided by both the capacitor and the inductor.

So, the correct answer is “Option D”.

Note:
An L-C circuit is also termed as a tank circuit, resonant circuit, or tuned circuit. L-C circuits also act as the main component in the various electronic devices like radio equipment, in the circuit like filters, oscillators, and tuners. when the L-C circuit will oscillate at its natural resonant frequency, it can store electrical energy.