Q 12-07-021NEETJEE MainMedium
A series LCR circuit with $R = 30\ \Omega$, $X_L = 60\ \Omega$ and $X_C = 20\ \Omega$ is connected to a $100$ V (rms) ac supply. The average power consumed in the circuit is
Answer: (D) $120$ W
Concept. Only the resistor dissipates power: $P = I_{\text{rms}}^2R$.
Step 1. Current. $Z = \sqrt{30^2 + 40^2} = 50\ \Omega$, $I = 2$ A.
Step 2. Power. $P = 4 \times 30 = 120$ W.
Answer. $120$ W (Option D).
Solution by Sreeraj P, M.Sc Physics