List of top Physics Questions on Resonance asked in CBSE Class XII

(i) Define the terms (I) resonant frequency, and (II) power factor of a series LCR circuit. For what value of the power factor will the power dissipated in the circuit be maximum?

(ii) An inductor of $\dfrac{5}{\pi}$ H, a capacitor of $\dfrac{50}{\pi}\ \mu\text{F}$ and a resistor of $400\ \Omega$ are connected in series across an ac voltage $v = 140 \sin(100\pi t)$ V. Calculate:

(I) impedance of the circuit, and

(II) rms value of current that flows in the circuit.

(Take $\sqrt{2} = 1.4$)

Using a phasor diagram, derive an expression for the impedance of a series LCR circuit connected to an ac source. What is meant by resonance in this circuit? Obtain expression for the resonant frequency of this circuit.

In a series LCR circuit connected to an ac source of voltage $V$ and frequency $\omega$, the power loss at resonance is:

Under what conditions the
• [(i)] impedance of the circuit is minimum?
• [(ii)] wattless current flows in the circuit?
Under what conditions the
• [(i)] impedance of the circuit is minimum?
• [(ii)] wattless current flows in the circuit?