Which type of particles does a smoke detector sense?

A smoke detector is designed to sense a variety of particles resulting from combustion, which can include both visible and invisible particles. When a fire occurs, it produces smoke containing a mix of gases and solid particles. These particles can vary in size and can be either light enough to remain airborne and invisible or larger and more readily visible.

Choosing the correct answer highlights the detector's ability to function effectively regardless of the visibility of the smoke it encounters. The sensor technology used in smoke detectors, such as ionization or photoelectric systems, is capable of detecting a range of smoke particles produced by different types of fires, which is essential for alerting occupants to potential dangers in a timely manner.