Practice question

**Current relative to voltage** in resistor in phase, φ=0°, power factor cos φ=1, maximum power, unlike inductor/capacitor where average power zero due to 90° phase shift, explaining why resistor heats while pure L/C does not. In an RC series circuit, Φ = tan⁻¹ ( (X_C/R) ) , where X_C = (1/ω C) . As frequency ( ω ) approaches infinity, X_C approaches zero, making Φ approach 0°, so the circuit becomes nearly resistive. Applying X_L = ωL, X_C = 1/ωC, Z = √(R² + (X_L - X_C)²), I_rms = V_rms/Z, P = V_rms I_rms cosφ, V_s/V_p = N_s/N_p, calculation gives It approaches 0°, consistent with