IAAI Certified Fire Investigator (CFI) Practice Test

The situation tests how heat sources can influence the movement of nearby items through convection. When a device operates at a wattage high enough to produce substantial heat—such as an incandescent bulb above about 25 watts—the surrounding air is warmed, rises, and creates a local draft. Lightweight objects can be carried along by this airflow, effectively being drawn toward the heat source. Incandescent light bulbs are a classic example because they waste a large portion of electrical power as heat, especially at higher wattages, so the heat output is enough to generate noticeable airflow that can pull nearby lightweight items toward the bulb. The other items listed aren’t primary heat sources in typical indoor scenarios and don’t produce the same sustained convective effect, so they don’t fit as well.