Why does an AC circuit with only an inductor exhibit a "wattless" current?
**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 a purely inductive AC circuit, the current lags the voltage by 90°. The power factor ( cos 90° = 0 ) is zero, meaning no average power is dissipated; the current is "wattless" because it only stores and releases energy without consuming it. Applying X_L = ωL, X_C = 1/ωC, Z = √(R² +
Ref: NCERT > Physics Book > Alternating Currents > Power in AC Circuits - Power Factor and Wattless Current