OSH Security Practice Test

What are some examples of motion sensors/detectors?

1. Infrared, ultrasonic, microwave

2. Keys, locks, deadbolt

3. Dampened, mercury sensor, inertia sensor, vibration sensor

4. Foil fine wire, glass breaker, shatter

The correct answer is: Infrared, ultrasonic, microwave

Motion sensors or detectors are essential components in security systems designed to detect movement within a certain area. The correct selection includes examples of sensor types that primarily serve this purpose. Infrared sensors detect motion by sensing changes in infrared radiation, typically from warm bodies moving within the sensor's range. Ultrasonic sensors work by emitting ultrasonic sound waves and measuring the reflection; when an object moves through the sound field, it changes the return signal, indicating motion. Microwave sensors operate similarly but use microwave pulses to detect changes in the frequency of the reflected waves when an object moves, making them effective for detecting motion even through certain materials. The other options listed consist of devices primarily focused on securing an area or object rather than detecting motion. Keys, locks, and deadbolts are traditional mechanical security devices used to prevent unauthorized access, while dampened, mercury, inertia, and vibration sensors may have specialized applications but do not generally represent primary motion detection technologies. Foil fine wire, glass breakers, and shatter sensors are typically used for detecting glass breakage rather than general motion.