While measuring power of a three-phase balanced load by the two-wattmeter method, the readings are $$100$$ $$W$$ and $$250$$ $$W$$. The power factor of the load is ___________.

A $$20$$-pole alternator is having $$180$$ identical stator slots with $$6$$ conductors in each slot. All the coils of a phase are in series. If the coils are connected to realize single-phase winding, the generated voltage is $${V_1}.$$ If the coils are reconnected to realize three-phase star-connected winding, the generated phase voltage is $${V_ 2}.$$ Assuming full pitch, single-layer winding, the ratio $${V_1}/{V_2}$$ is

There are two generators in a power system. No-load frequencies of the generators are $$51.5$$ $$Hz$$ and $$51$$ $$Hz,$$ respectively, and both are having droop constant of $$1$$ $$Hz/MW.$$ Total load in the system is $$2.5$$ $$MW.$$ Assuming that the generators are operating under their respective droop characteristics, the frequency of the power system in $$Hz$$ in the steady state is ____________.

A synchronous generator is connected to an infinite bus with excitation voltage $${E_f} = 1.3\,pu.$$ The generator has a synchronous reactance of $$1.1$$ $$pu$$ and is delivering real power $$(P)$$ of $$0.6$$ $$pu$$ to the bus. Assume the infinite bus voltage to be $$1.0$$ $$pu.$$ Neglect stator resistance. The reactive power $$(Q)$$ in $$pu$$ supplied by the generator to the bus under this condition is ____________.