The density of an object is the mass of the object compared to its volume. The equation for density is: Density = mass/volume or D = m/v. Each substance has its own characteristic density because of the size, mass, and arrangement of its atoms or molecules.
Rating Newest Oldest. Best Answer: The knock sensor is basically a microphone. Its there to listen for spark knock which is also called detonation, pinging, and pre ignition. This is the condition inside the engine where the fuel begins to burn before its supposed to. It sounds like someone rattling a can of marbles. It can easily destroy the internals of an engine.
An occupancy sensor is a lighting control device that detects occupancy of a space by people and turns the lights on or off automatically, using infrared, ultrasonic or microwave technology. Occupancy sensors are typically used to save energy, provide automatic control, and comply with building codes. Three basics types of occupancy sensors are: 1  Passive infrared sensor, which works on heat movement detection.