Flame detectors detect ___________ and __________ light spectrums.

Flame detectors detect ___________ and __________ light spectrums.

• A. Ultraviolet / infrared
• B. Visible / infrared
• C. Ultraviolet / visible
• D. Microwave / infrared

Answer: (A)

Flame detectors are designed to respond to radiation emitted by flames in specific parts of the spectrum. They monitor ultraviolet and infrared light because flames emit strongly in both ranges: UV from excited species produced during combustion and IR from the flame’s heat. Using both wavelengths allows for fast detection (UV) and reliable sensing through smoke or lighting conditions (IR), while also reducing false alarms by distinguishing flame signatures from other heat or light sources. Visible light isn’t as reliable for flame detection due to background lighting and smoke, and microwaves aren’t used in standard flame detectors.

Flame detectors are designed to respond to radiation emitted by flames in specific parts of the spectrum. They monitor ultraviolet and infrared light because flames emit strongly in both ranges: UV from excited species produced during combustion and IR from the flame’s heat. Using both wavelengths allows for fast detection (UV) and reliable sensing through smoke or lighting conditions (IR), while also reducing false alarms by distinguishing flame signatures from other heat or light sources. Visible light isn’t as reliable for flame detection due to background lighting and smoke, and microwaves aren’t used in standard flame detectors.