Red Seal Electrician Practice
Magnetism and electromagnetismQuestion 869 of 1506

Why is the magnetic equivalent of Ohm’s Law harder to use than the electrical version?

  1. Reluctance changes with the amount of flux in the material.
  2. Magnetic circuits have no equivalent of voltage at all.
  3. Magnetic flux cannot pass through iron.
  4. The length of the material has no effect on the result.
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Correct answer: Reluctance changes with the amount of flux in the material.

It is like a resistor whose value changes with current, so the relationship is not linear.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 14.3: Magnetic Units of Measurement

Practice magnetism and electromagnetism

Questions last reviewed: 18 October 2026