What component identifies unauthorized entry via infrared, ultrasonic, microwave, or pressure-based detection of movement?

What component identifies unauthorized entry via infrared, ultrasonic, microwave, or pressure-based detection of movement?

• A. Motion detectors
• B. CCTV
• C. Alarm bells
• D. Sensors

Answer: (D)

Sensors are the devices that detect physical changes in the environment using various modalities such as infrared, ultrasonic, microwave, or pressure. Each of these methods is a way sensors sense movement or intrusion, turning that information into a signal that can trigger an alert. Motion detectors are a specific type of sensor focused on detecting movement, often using infrared or microwave tech, but the question describes multiple sensing methods, so the broad category that covers all of them is sensors. CCTV records and can reveal intrusions after the fact, and alarm bells produce audible alerts rather than the detection itself.

Sensors are the devices that detect physical changes in the environment using various modalities such as infrared, ultrasonic, microwave, or pressure. Each of these methods is a way sensors sense movement or intrusion, turning that information into a signal that can trigger an alert. Motion detectors are a specific type of sensor focused on detecting movement, often using infrared or microwave tech, but the question describes multiple sensing methods, so the broad category that covers all of them is sensors. CCTV records and can reveal intrusions after the fact, and alarm bells produce audible alerts rather than the detection itself.