Question

In an $L-C-R$ series circuit, the values of $R, X_{L}$ and $X_{C}$ are $120\, \Omega, 180\, \Omega$ and $130\, \Omega$, what is the impedance of the circuit?

• A. $120\, \Omega$
• B. $130\, \Omega$
• C. $180\, \Omega$
• D. $330\, \Omega$

Answer 1

Answer: (B)

Given, $R=120\, \Omega$
$X_{L}=180\, \Omega, X_{C}=130\, \Omega$
The impedance of $L-C-R$ circuit
$Z=\sqrt{R^{2}+\left(X_{L}-X_{C}\right)^{2}}$
$Z=\sqrt{(120)^{2}+(180-130)^{2}}=130\, \Omega$