SignalPrep
Basic Qualification · B-005 Basic electronics and theory · B-005-009-009

If you wire two 20-millihenry inductors in parallel, what is the inductance of the combination?

  1. A80 millihenries
  2. B5 millihenries
  3. C10 millihenries
  4. D40 millihenries

Correct answer: C — 10 millihenries. From the official ISED question bank, verified word for word.

Why

When two identical inductors, which are coils that store energy in a magnetic field, are wired in parallel, the total inductance drops to exactly half of one component's value. The full explanation — and one for every question — is in Pro.

Practise this section

Basic electronics and theory is section B-005 of the Basic exam: The theory: Ohm's law, power, series and parallel circuits, AC and DC, frequency and wavelength, decibels, and the metric prefixes the exam leans on.

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