Give one application of the photoelectric effect. - Leaving Cert Physics - Question (a) - 2009

One application of the photoelectric effect is in burglar alarms. These systems utilize light sensors that detect changes in light levels caused by an intruder passing through the sensor's field of vision. When light strikes the sensor, it generates a current, triggering the alarm. Other applications include automatic doors, which rely on photoelectric sensors to open when a person approaches, and control of burners in central heating systems, where the photoelectric effect regulates operations based on the presence of light. Additionally, the effect is used in sound tracks of films, enabling the conversion of light signals into sound.