Nebraska Security Guard State Practice Exam

Motion sensors/detectors are devices that detect or measure changes in the physical environment to determine the presence of movement. Option A provides examples of types of motion sensors based on the technology they use. Infrared sensors use heat energy to detect movement, ultrasonic sensors use sound waves, and microwave sensors use radio waves. Options B, C, and D are incorrect because they refer to keys, locks, deadbolts and various materials or devices that do not measure or detect motion. Additionally, while some of the options listed in C and D may respond to motion, they do not fit the definition of a motion sensor/detector.