Basic Qualification · B-005 Basic electronics and theory · B-005-008-006
What is the "decibel" used for?
- A To describe a waveform on an oscilloscope
- B To describe very high frequency radio waves
- C To measure a single side band signal
- D To measure the ratio of two signals
Correct answer: D — To measure the ratio of two signals. From the official ISED question bank, verified word for word.
Why
The decibel is a unit used to measure the ratio of two signals, such as comparing how much stronger one radio transmission is than another. The full explanation — and one for every question — is in Pro.
Practise this section
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.