A Radiant Energy Detector detects flames by looking for specific portions of which spectrum?

• A. A type of detector that looks for specific portions of the visible and invisible light spectrum produced by flames, sparks, or embers.
• B. A detector that senses smoke by heating it.
• C. A detector that measures humidity.
• D. A detector that detects carbon monoxide.

Answer: (A)

Radiant energy detectors respond to the light energy emitted by flames. Flames don’t just give off heat; they emit radiation across specific portions of the spectrum, including visible light and parts of the spectrum that aren’t visible to the eye (such as ultraviolet and infrared). By tuning sensors to these flame-emission bands, the detector can recognize the characteristic radiant signature of a flame, sparks, or embers quickly and distinguish it from other heat sources. Detectors that sense smoke, measure humidity, or detect carbon monoxide rely on different signals, so they don’t use the flame’s spectral signature the way radiant energy detectors do.