Question 26 of 30
Fire alarm system thermostats are actuated by:
A
Air pressure changes inside trunk compartments
B
The difference in thermal expansion of two dissimilar metals
C
Light scattering effects across laser sensors
D
Moisture tracking limits inside structural wiring panels
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Answer & Explanation
The correct answer is Option B: The difference in thermal expansion of two dissimilar metals.
Thermostats used in fire alarm systems, particularly bimetallic types, operate based on the principle that two different metals expand at different rates when heated. This differential expansion causes the strip to bend, closing an electrical contact and triggering an alarm.