What activates a beam smoke detector?

A beam smoke detector operates based on the principle of light interruption. It consists of a light source, usually an infrared beam, and a receiver. When smoke enters the path of the beam, it scatters the light as it travels from the source to the receiver. Eventually, if the amount of light received falls below a certain threshold due to the scattering caused by the smoke particles, the detector activates an alarm.

This functionality directly relates to the concept of a broken light beam, as the presence of smoke disrupts the light transmission from the source to the receiver. Hence, the activation of a beam smoke detector is contingent on this interruption caused by smoke particles, validating that the correct answer involves recognizing the significance of the light beam's integrity in smoke detection systems.