Single Phase Alternator
A single-phase alternator is a device used to generate alternating current (AC) electricity. It consists of a rotor and a stator. The rotor is driven by a mechanical energy source, such as an engine or a turbine, and the stator is the stationary part of the alternator.

Synchronous Reactance
The synchronous reactance of an alternator is a parameter that represents the opposition to the flow of alternating current through the alternator. It is denoted by Xs and is measured in ohms. The synchronous reactance depends on the design and construction of the alternator.

In this case, the single-phase alternator has a synchronous reactance of 217 ohms and a negligible resistance. This means that the opposition to the flow of current is mainly due to the reactance rather than the resistance.

Purely Capacitive Load
A purely capacitive load is a type of load that only consists of capacitance. It does not have any resistance or inductance. When an AC voltage is applied to a purely capacitive load, the current leads the voltage by 90 degrees.

In this scenario, the single-phase alternator is supplying a purely capacitive load. The load requires a current of 10 A and operates at a voltage of 200 V.

Generated EMF
The generated EMF (electromotive force) of the single-phase alternator can be calculated using Ohm's law. Ohm's law states that the voltage is equal to the product of the current and the impedance.

In this case, the impedance is equal to the synchronous reactance because the resistance is negligible. Therefore, the generated EMF can be calculated as follows:

EMF = Current * Impedance
EMF = 10 A * 217 ohms
EMF = 2170 V

Therefore, the generated EMF of the single-phase alternator supplying a purely capacitive load at 10 A and 200 V is 2170 V.