AIIMS 2018 Physics AC Circuits MCQ Question

Option A, $P_{\text{avg}} = V_{\text{rms}} \cdot I_{\text{rms}} \cdot \cos \phi$, is correct because it represents the formula for average power loss in an AC circuit, where $V_{\text{rms}}$ is the root mean square voltage, $I_{\text{rms}}$ is the root mean square current, and $\cos \phi$ is the power factor that accounts for the phase difference between voltage and current. Option B is incorrect as it suggests a formula that includes resistance and reactance but does not directly represent average power loss; instead, it describes a relationship that is more complex and not standard for average power calculation. Understanding these formulas is crucial for analyzing power in AC circuits, emphasizing the role of phase relationships in power efficiency.