If a step-down transformer has a 2 to 1 turn ratio and 140 MWs power is entering, what is the output power?

• A. 150 MWs
• B. 140 MWs
• C. 280 MWs
• D. 70 MWs

Answer: (B)

In a transformer, the voltage and current relationships are determined by the turns ratio. The output power of an ideal transformer (one that does not experience losses) remains equal to the input power. This means that regardless of the turns ratio, the power entering the transformer is the same as the power exiting the transformer.

In this case, since you have a step-down transformer with a 2 to 1 turns ratio, it is reducing the voltage while increasing the current proportionally. The input power is given as 140 MWs. Therefore, for an ideal transformer, the output power will also be 140 MWs. This relationship holds true as transformers operate on the principle of conservation of energy, so they typically don't create or destroy power, only convert it within different voltage and current levels.

Thus, the output power remains the same as the input power at 140 MWs, confirming that the correct answer is indeed the same as the input value.