Red Seal Electrician Practice
TransformersQuestion 1093 of 1506

The primary of a transformer has 400 times the inductance of its secondary. What is the turns ratio, primary to secondary?

  1. 400:1
  2. 200:1
  3. 20:1
  4. 2:1
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Correct answer: 20:1

Inductance goes with the square of the turns. The turns ratio is the square root of 400, which is 20.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.2: Step-up and Step-down Transformers

Practice transformers

Questions last reviewed: 18 October 2026