A $9$KVA, $208$V$,1200$rpm$,3-$phase, $60$Hz$,$ star connected, synchronous generator, a field

winding resistance of $4\mathrm{.}5.$ The armature winding in pedance is $0\mathrm{.}3+$j$5$ per phase. When the

generator operates at its full load & $0\mathrm{.}8$ pf lagging, the field winding current is $5$A$.$ The

rotational loss is $500$W$.$ Determine:

a$)$ The voltage regulation.

b$)$ The efficiency of the generator.

c$)$ The torque applied by the prime mover