When a 250-V, 50 hp, 1000 rpm d.c shunt motor is used to supply rated output power to a constant torque load, it draws an armature current of 160A. The armature circuit has a resistance of 0.04 2 and the rotational losses are equal to 2 KW. An external resistance of 0.5 is inserted in series with the armature winding. For this condition compute (i) (ii) (iii) the speed the developed power the efficiency assuming that the field loss is 1.6 K.W (8+4+4)