what is meant by resonance in a tuned circuit?

Answer 1

Discharging and charging of Capacitors coupled with the inductance setup in inductors.

Answer 2

A resonant tuned circuit is composed of capacitance,inductance and resistance. The resistance is not required but is a feature of the other components.
The circuit can be a series resonator or a parallel.
The feature of a resonant circuit is that the impedance due to capacitance and the impedance due to inductance are equal.
Since the inductive impedance is proportional to the frequency and the capacitive impedance is inversely proportional, then we can see that the resonant frequency is unique to that combination of inductance and capacitance.
Any resistance in the circuit causes a widening of the frequency response.
When a series L/C circuit is resonant, the AC current through it will be maximum.
With a parallel L/C circuit the current in the network is maximum, but because this current is circulating in the L/C network, the impedance looking into it from the outside is at its maximum so line current is minimum.
Thus a series resonant circuit is a bandpass filter and a parallel resonant circuit is a band blocking filter.

Answer 3

This is a question in Physics, and not Chemistry. In a tuned circuit, the impedance changes with the frequency. For series resonance the impedance becomes zero, and for parallel resonance, it becomes theoretically infinity.