Previous Year NEET Question- Lcr Circuits

• 2019:

Q11. A series LCR circuit with L = 1.0 H, C = 2.0 μF and R = 50Ω is connected to a variable frequency 220 V ac source. Calculate the Q-factor of the circuit at resonance.

The Q-factor of a series LCR circuit is given by

$$Q = \frac{1}{R\sqrt{LC}}$$

Substituting the values of L, C, and R, we get

$$Q = \frac{1}{50\sqrt{1.0\times2.0\times10^{-6}}} = 31.6$$

Therefore, the Q-factor of the circuit at resonance is 31.6.

• 2018:

Q3. An LCR circuit is in resonance. If the resistance is increased, the current in the circuit will: (A) increase (B) decrease (C) remain the same (D) become zero

The answer is (B).

When an LCR circuit is in resonance, the current in the circuit