Heat transfer in the form of invisible electromagnetic waves is called what?

Heat transfer in the form of invisible electromagnetic waves is known as radiation. This process involves the transfer of thermal energy through electromagnetic waves, which can occur in a vacuum, as well as in a medium like air or water. Since radiation does not require direct contact between the heat source and the object being heated, it is distinct from the other modes of heat transfer.

In contrast, conduction is the process where heat is transferred through direct contact between materials, where higher-energy particles collide with lower-energy particles. Convection involves the transfer of heat through the movement of fluids, where warmer areas of a liquid or gas rise and cooler areas sink, creating a circulation pattern. Emission pertains specifically to the release of energy in the form of waves, but it does not represent the broader category of heat transfer that includes radiation. Hence, the definition and characteristics of heat transfer in the form of invisible electromagnetic waves align precisely with the concept of radiation.