Which of the following uses a photoelectric device to trigger an alert?
A.
Automatic dial-up alarms
B.
Heat-activated fire detectors
C.
Flame-activated fire detectors
D.
Smoke-activated fire detectors
Explanation:
Smoke-activated detectors use photoelectric optical detectors to
detect changes in light intensity.
A deeper clarification:
Photoelectric detectors are classified as either beam or refraction. Beam detectors operate on the principle of light and a receiver. Once enough smoke enters the room and breaks the beam of light, the alarm is sounded. The refraction type has blocker between the light and the receiver. Once enough smoke enters the room, the light is deflected around the beam to the signal.
Tipton, Harold F. (2010-04-20). Official (ISC)2 Guide to the CISSP CBK, Second Edition ((ISC)2 Press) (Kindle Locations 14358-14360). Taylor & Francis. Kindle Edition.
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