A hand placed near a hot stove or fireplace is quickly heated by which mode of heat transfer?

• A. Radiation
• B. Convection
• C. Conduction
• D. Refrigeration

Answer: (A)

Radiation is the transfer of heat through electromagnetic waves from a hot object to another object without needing contact. A hand held near a hot stove is heated mainly by infrared radiation emitted by the hot surface; those rays travel through the air and warm the skin directly, so you feel the heat even before any air around you becomes noticeably warm. Conduction would require direct touch with the hot surface, and convection would involve moving hot air transferring heat, which isn’t the primary mechanism here. Refrigeration isn’t a heat transfer mode.