7.7 The results of the OC and SC tests on a single-phase, 20 kVA, 2200:220 V, 60 H: transformer are: OC test on the secondary side with primary open V = 220 V, 1= 4.2 A and W= 148 W SC test on the primary side with secondary short circuited V = 86 V, I = 10.5 A and W= 360 W Detemine the regulation and efficiency at full-load and at 0.8 power factor lag.