1. A two-winding, iron-core transformer is shown is Fig 1.P-1. N ₁ = 500 turns, N ₂ = 100 turns, and ? _R = 4000. Calculate L _m1 , L _m2 , and L ₁₂ . The resistance of coils 1 and 2 is 2? and 4?, respectively. If the voltage applied to coil is v _{1 =} 10cos400t, calculate the voltage appearing at the terminals of coils 2 when 2 is open-circuited.

2. Repeat Problem 1 if the iron core has an air gap of 0.2cm in length and is cut through the complete cross section. Assume that fringing does not occur in the air gap that is the effective cross-sectional area of the air gap is 25cm ² .

30 cm N 5 cm 30 cm N 5 cm Figure 1.P-1 Two-winding, iron-core transformer.