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. X_C = (1/ω C) = (1/314 × 18 × 10⁻⁶) ≈ 176.8 Ω . Z = √(R² + X_C²) = √(45² + 176.8²) = √(2026 + 31258.24) ≈ 182.4 Ω . 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 182.4 Ω, consistent with phasor analysis and resonance condition X_L = X_C.