Practice question

**Average power in LCR** P_avg = V_rms I_rms cos φ, cos φ = R/Z power factor, φ phase between V and I, tan φ = (X_L - X_C)/R. For R=80 Ω, X_L=100 Ω, X_C=40 Ω, X_L-X_C=60 Ω, Z=√(80²+60²)=100 Ω, cos φ=0.8, V_rms=240 V, I_rms=2.4 A, P=240×2.4×0.8=460.8 W, only R dissipates. In an RL series circuit, power factor cos Φ = (R/Z) , where Z = √(R² + X_L²) and X_L = ω L . Increasing inductance increases X_L , which increases Z , reducing cos Φ (closer to 0), as the circuit becomes more inductive. Applying X_L = ωL, X_C = 1/ωC, Z = √(R²