Which is not a valid method for detecting smoke or flame?
A.
Temperature
B.
Ionization
C.
Photoelectric
D.
Ultraviolet
Explanation:
Answer A is correct; temperature sensors are used in heat detectors, not in smoke or flame detectors.Incorrect Answers and Explanations: B, C, and D: Answers B, C, and D are incorrect. Ionization and photoelectric sensors are used in smoke detectors. Ultraviolet sensors are used in flame detectors.