Question

Do electric circuits exhibit harmonic motion?

Answer 1

Explanation:

1. In a circuit containing an inductor and a capacitor, oscillations can occur because of the transfer of energy between the electric field and the magnetic field.
2. Initially, if the capacitor of capacitance $C$ contains charge $q$ before closing the circuit, the energy stored in it will be $E=\frac{q^2}{2C}$.(Figure a)
3. When the switch is closed, the capacitor begins to discharge and there is current flow in the circuit (Figure b). The current produces a magnetic field in the inductor.
4. Again when the switch is open, the capacitor enters a charging phase, but the polarity is reversed (Figure c) due to the previous discharge of positive charge from one plate making it negatively charged with respect to the other plate.
5. Now when the switch is closed, the current flow is reversed. (Figure d).
6. Hence, Figures (a) to (d) depict harmonic oscillation of the stored charge with alternating directions of current.

The equivalent graph of the above-mentioned phenomena is given below.

Hence, electric circuits can exhibit harmonic motion.