TransformersQuestion 1433 of 1506

A transformer must change 240 V to 120 V. The primary winding has 400 turns. How many turns must the secondary winding have?

  1. 400 turns
  2. 200 turns
  3. 800 turns
  4. 600 turns
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Correct answer: 200 turns

Ns = Np × (Vs ÷ Vp) = 400 × (120 ÷ 240) = 200 turns.

Source: Computed, 1.1: What is Alternating Current (AC)?

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Questions last reviewed: 18 October 2026