In an ideal transformer, if the primary voltage is doubled and the turns ratio remains the same, what happens to the secondary current?
Correct answer: A. Doubles
- A. Doubles
- B. Halves
- C. Remains the same
- D. Becomes four times
Explanation
With the turns ratio fixed, doubling the primary voltage doubles the secondary voltage, and for a given load resistance the secondary current rises in proportion by Ohm's law. The power drawn from the primary rises fourfold to match. The halving answer would apply to comparing primary with secondary current at a fixed input, which is a different question.
This question appeared on the UHS MDCAT 2025 paper, which you can sit online with every answer explained.
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About Transformers
Transformers transfer alternating electrical energy between coils by mutual induction, with voltage ratio determined by the turns ratio. The topic covers step-up and step-down transformers, current changes, ideal power conservation and practical losses such as heating and flux leakage. A transformer requires changing magnetic flux, so it does not operate with steady direct current.
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