(a) Describe a simple single phase transformer (6)

(b) A 15 kVA, 440/110 volt, 50 cycle/sec, single-phase transformer has primary and secondary resistance of 0.12 ohm and 0.0077 ohm respectively. The iron loss of the transformer is 0.16 kW. Calculate the efficiency of the transformer

(i) on full load unity power factor

(ii) on 80 percent full load at a power factor of 0.9 lagging. (10)