Question

At resonant frequency the current amplitude in series LCR circuit is:

• A. maximum
• B. minimum
• C. zero
• D. infinity

Answer 1

The correct option is A

maximum

1. This is the circuit diagram of a series LCR circuit.
2. Impedance of series LCR circuit is given by$Z=\sqrt{R^2+{(X_L-X_c)}^2}$.
3. Also, $I=\frac{V}{\sqrt{R^2+(X_L-X_C)}}$
4. At the resonant frequency,$X_L=X_c$.
5. Therefore, impedance $Z$is minimum.
6. Therefore, the current $I$ will be maximum.

Hence, option (a) is correct.