Which type of smoke detector is most commonly used by consumers and detects combustion products using radioactive material?

The ionization detector is the type of smoke detector most commonly used by consumers that detects combustion products through the use of radioactive material. This type of detector incorporates a small amount of radioactive material, which ionizes the air within a sensing chamber. When smoke enters this chamber, it disrupts the ionization process, reducing the current flow and triggering the alarm.

Ionization smoke detectors are particularly effective at detecting fast-burning fires, where flames produce small combustion particles that can quickly disrupt the ionization process. Because of their sensitivity to these types of fires, they are widely favored in residential settings.

The other options listed do not utilize radioactive materials in their design. Photoelectric detectors use a light source to detect smoke, while optical detectors also rely on light but often function through different mechanisms such as scatters of light. Ultrasonic detectors are more specialized and not typically used for smoke detection at all.