Question

Which of the following are commonly used as sensors in an intrusion alarm system? A) photoelectric beams B) audible sounds C) FM radio frequencies D) computer monitors E) private alarm companies

Answer 1

Photoelectric beams, audible sounds, and FM radio frequencies are commonly used as sensors in an intrusion alarm system.

Step-by-step explanation:

Commonly used sensors in an intrusion alarm system include:

1. Photoelectric beams: These sensors use beams of light to detect if someone or something interrupts the beam, triggering the alarm.
2. Audible sounds: Some alarm systems use sound wave sensors to pick up on specific frequencies associated with certain events, such as breaking glass or the sound of someone trying to force open a door or window.
3. FM radio frequencies: Radio frequency sensors can be used to detect motion or changes in the environment.