A coil of inductance and a capacitor of capacitance are connected in series with a…
PHYSICS · Multi-part · CBSE · Physics · Alternating Current · Alternating Current
Problem
A coil of inductance L and a capacitor of capacitance C are connected in series with a resistor R to an AC source whose frequency can be varied over a wide range.
(i) Explain what is meant by electrical resonance in the above circuit.
(ii) With the help of a labelled phasor diagram, describe qualitatively how (a) the impedance of the circuit and (b) the phase difference between the current and the applied voltage change as the frequency is increased from well below the resonant value to well above it.
(iii) At resonance the instantaneous voltages across the inductor and the capacitor may each exceed the supply voltage, yet the current in the circuit attains its maximum value. Explain how this is possible.