Massachusetts Security Officer Practice Exam

In the field of security systems, motion detectors or sensors are used to detect physical movement in a given area. They can be used as part of a security system or as standalone devices in areas requiring specific surveillance or protection. Infrared sensors, ultrasonic sensors, and microwave sensors are all types of motion detectors. Infrared sensors, also known as Passive Infrared Sensors (PIR), detect changes in the heat signatures. They work by detecting the change in heat when an object, such as a human, passes in front of them. Ultrasonic sensors work by emitting sound waves that are above the range of human hearing. When these waves hit a moving object, they bounce back to the sensor. The sensor then calculates the distance based on the time it took for the echo to return, thus detecting motion. Microwave sensors emit microwave signals and measure their reflection off objects to detect movement. They can cover a large area and are typically used in big commercial spaces or outdoor areas. So, the examples given in choice A- Infrared, ultrasonic, microwave, are the correct types of motion sensors/detectors used in security systems.