15–40 The self and mutual inductances of a transformer can be calculated from measurements of the steady-state ac voltages and currents with the secondary winding open-circuited and short-circuited. Suppose the measurements are |V1 | = 60 V,

| I1 | = 120 mA, and |V2 | = 180 V when the secondary winding is open. When the secondary is shorted, the measurements are | I1 | = 10A and | I2 | = 5A. All measurements were made at f = 60 Hz. Find L1, L2, and M.