Alternating Current: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Alternating Current. Understanding the underlying formula is key to arriving at the correct answer below:

At resonance in a series LCR circuit, $X_L = X_C$, meaning the circuit is purely resistive.
Total impedance $Z = R$.
Power loss is $P = I_{rms}^2 Z \cos\phi$.
Since $\cos\phi = 1$ and $Z = R$, $P = I^2 R$.