10. A short-shunt compound d.c. Generator supplies a current of 100 A at a voltage of 220 V. If the resistance of the shunt field is 50 52, of the series field 0.025 £2, of the armature 0.05 £2, the total brush drop is 2 V and the iron and friction losses amount to 1 kW, find (a) the generated e.m.f. (b) the copper losses (c) the output power of the prime-mover driving the gen- erator and (d) the generator efficiency.​