Practice question

**Transformer principle** alternating current in primary creates changing flux linking secondary, emf induced e = -N dΦ/dt, flux same through both, so V∝N. For N_p=550, N_s=1100, V_p=110 V rms, V_s= V_p×N_s/N_p=220 V, step-up factor 2, efficiency <100% due to copper, iron, hysteresis losses. X_L = ω L , ω = 2π × 50 = 314 rad/s . L = 40 × 10⁻³ H . X_L = 314 × 0.04 = 12.56 Ω . RMS current: I = (V/X_L) = (230/12.56) ≈ 18.31 A . 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