You can't determine the output voltage of a transformer by knowing kva. Transformers will be marked as to input and output voltages. Some will have multiple input and output voltages. The output...
Because commonly we say : some hardware (e.g. transformer, speaker etc.) has XX Watts which corresponds to Real(Active) power (usually the only one measured by old traditional counters) but we have...
I assume this question is asking why transformers are rated in VA as opposed to watts. The reason is because the transformer doesn't not care about the phase angle relationship of the voltage applied...