Final answer:
Radiant heaters emit infrared radiation, which heats only those objects in its path.
Step-by-step explanation:
Radiant heaters emit infrared radiation, which heats only those objects in its path. Infrared radiation is a form of electromagnetic radiation that is invisible to the human eye but can be detected by thermal imaging cameras. Radiant heaters work by converting electrical energy into infrared radiation, which is then absorbed by objects in the environment, causing them to heat up.