Which type of smoke detector responds to smoke particles by utilizing a light source and photosensitive sensor in a unique arrangement?

The correct answer is the type of smoke detector that operates on the principle of light refraction combined with the scattering of light due to smoke particles. In this setup, a light source emits a beam of light that is aimed to pass through the sensing chamber. When smoke particles enter the chamber, they cause the light to refract and scatter in different directions. The photosensitive sensor detects these changes in light intensity, signaling the presence of smoke.

This mechanism is particularly effective because it can respond quickly to slow-smoldering fires which produce a lot of smoke before flames are visible. The unique arrangement of the light source and photosensitive sensor, in conjunction with the refraction principle, allows for the reliable detection of smoke without responding to non-smoke-related particulates.

The other types of detectors listed may focus more on different principles of light interaction or detection methods, but they do not emphasize the specific relationship between light refraction and smoke particle detection as effectively as this smoke detector type.