Question

The $LC$ parallel resonant circuit

• A. has a very high impedance
• B. has a very high current
• C. acts as resistance of very low value
• D. has zero impedance

Answer 1

Answer: (A)

In LC parallel resonant circuit, the impedance is given by
$Z=\frac{\left(X_C\right)\left(X_L\right)}{X_C-X_L}$
In LC parallel resonant circuit, at the resonant frequency we have,
$X_C=X_L$
$\therefore Z=\infty$
Also, For pure resistor, $Z=R$
Hence,
In LC parallel resonant circuit, the impedance is near to infinity or very high.
Since, the impedance(resistance) is maximum, the current is negligible or zero it circulates back and forth between components without involving the source..