Q. The efficiency of a 400-kVA, single-phase, 60-Hz transformer is 98.77% when delivering full-load current at 0.8 power factor, and 99.13%with half rated current at unity power factor. Calculate:
(a) The iron loss.
(b) The full-load copper loss.
(c) The efficiency at 3/4 load, 0.9 power factor