What is heat transfer by microwave energy called?

Heat transfer by microwave energy is referred to as radiation. In this context, radiation occurs when energy is transferred in the form of electromagnetic waves, such as microwaves. These waves can travel through space and transfer energy directly to an object without needing any physical medium, such as air or liquid.

In contrast, conduction involves heat transfer through direct contact between materials, where energy is passed from one particle to another. Convection refers to the transfer of heat through a fluid (gas or liquid) where warmer sections of the fluid rise and cooler sections sink, creating a flow that distributes heat.

Therefore, the correct classification of heat transfer induced by microwaves is radiation, as it uniquely relies on the transmission of energy through electromagnetic waves rather than through material contact or fluid movement.