CISSP Practice Exam 2025 – Complete Prep Guide

Microwave motion detectors identify movement by emitting microwave energy and analyzing the reflections of these waves. When an object moves within the sensor's range, it alters the pattern of the reflected microwave signals, which the detector interprets as motion. This technology is particularly effective in detecting motion over a wide area and can penetrate through certain materials that can obstruct other types of signals.

In contrast, passive motion detectors rely on detecting changes in infrared radiation emitted by objects (including people) in their environment, rather than actively sending out energy. Ultrasonic motion detectors utilize sound waves above the human hearing range to sense motion, while infrared devices operate based on changes in heat. Each method has distinct characteristics and applications, but microwave motion detection is specifically characterized by its use of electromagnetic waves to sense movement, making it the correct choice.