SignalPrep
Basic Qualification · B-004 Circuit components · B-004-002-008

What semiconductor device glows different colours, depending upon its chemical composition?

  1. AA vacuum diode
  2. BA light-emitting diode
  3. CA fluorescent bulb
  4. DA neon bulb

Correct answer: B — A light-emitting diode. From the official ISED question bank, verified word for word.

Why

A light-emitting diode is a semiconductor that glows when electricity passes through it, and the specific colour it produces depends entirely on the chemical materials used to build the chip. The full explanation — and one for every question — is in Pro.

Practise this section

Circuit components is section B-004 of the Basic exam: The parts inside the box: resistors, capacitors, inductors, diodes, transistors, tubes and what each does in a circuit.

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