The saw-tooth voltage waveform shown in the figure is fed to a moving iron voltmeter. Its reading would be close to _______.

Two ammeters $$X$$ and $$Y$$ have resistances of $$1.2$$ $$\Omega $$ and $$1.5$$ $$\Omega $$ respectively and they give full-scale deflection with $$150$$ $$mA$$ and $$250$$ $$mA$$ respectively. The ranges have been extended by connecting shunts so as to give full scale deflection with $$15$$ $$A.$$ The ammeters along with shunts are connected in parallel and then placed in a circuit in which the total current flowing is $$15A.$$ The current in amperes indicated in ammeter $$X$$ is __________.

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 ___________.

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 ____________.