The two signals $$S1$$ and $$S2,$$ shown in figure, are applied to $$Y$$ and $$X$$ deflection plates of an oscilloscope.

The waveform displayed on the screen is

A periodic waveform observed across a load is represented by $$$V\left( t \right) = \left\{ {\matrix{ {1 + \sin \,\omega t} & {0 \le \omega t < 6\pi } \cr { - 1 + \sin \,\omega t} & {6\pi \le \omega t < 12\pi } \cr } } \right.$$$
$$6\pi \le \omega t < 12\,\pi $$
The measured value, using moving iron voltmeter connected across the load, is

In the bridge circuit shown, the capacitors are loss free. At balance, the value of capacitance C₁ in microfarad is ________.

A non-salient pole synchronous generator having synchronous reactance of $$0.8$$ $$pu$$ is supplying $$1$$ $$pu$$ power to a unity power factor load at a terminal voltage of $$1.1$$ $$pu$$. Neglecting the armature resistance, the angle of the voltage behind the synchronous reactance with respect to the angle of the terminal voltage in degrees is ____________.