A transformer is used to change theI. resistanceII. capacitanceIII. currentIV. voltage
Correct answer: D. III or IV.
- A. I and II.
- B. I and IV.
- C. II and III.
- D. III or IV.
Explanation
A transformer is an electrical device used to transfer electrical energy between two or more circuits through electromagnetic induction. It primarily functions to change the voltage levels - either stepping up (increasing) or stepping down (decreasing) the voltage, which in turn affects the current due to the power conservation principle (Power = Voltage × Current). Therefore, transformers are used to change the current and voltage levels in a circuit.Option A: 'I and II' is incorrect because transformers do not change resistance (I) or capacitance (II).Option B: 'I and IV' is incorrect because while transformers change voltage (IV), they do not change resistance (I).Option C: 'II and III' is incorrect because transformers do not change capacitance (II) though they do affect current (III).Option D: 'III or IV' is correct because transformers are designed to change both current (III) and voltage (IV) depending on how they are configured.
Last updated
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.
Practise Electromagnetic Induction
288 free Electromagnetic Induction MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.