The Correct Answer Is A

When a transformer is switched on to a voltage more than the rated voltage, the power factor will deteriorate. This is due to the fact that the transformer is not able to handle the additional voltage and will be overloaded.

The overload will cause an increase in reactive power, which will lead to a decrease in the power factor. The output voltage will also increase proportionately, but the power handling capability remains the same. If the voltage is raised enough, the transformer will saturate, resulting in further deterioration of the power factor. To ensure that a transformer operates efficiently, it is important to ensure that it is not overloaded and that the supply voltage is kept within the rated range.