Practice question

**Impedance behavior at high frequencies** X_L=ωL dominates ∝ f, X_C=1/ωC →0, so Z≈√(R²+X_L²)≈X_L large, current small, circuit inductive, φ→90°, at low frequencies X_C large, Z≈X_C, capacitive, φ→-90°, at intermediate resonance Z minimal =R. ω₀ = (1/√(L C)) . L = 5 H , C = 80 × 10⁻⁶ F . ω₀ = (1/√(5 × 80 × 10⁻⁶)) = (1/√(4 × 10⁻⁴)) = 50 rad/s . f₀ = (50/2 × 3.14) ≈ 7.96 Hz . 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 8 Hz, consistent with