Looking for Heat Transfer MCQs for GATE Exam? Thousands of them are here! It is a discipline of thermal engineering & Mechanical Engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat-transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer. While these mechanisms have distinct characteristics, they often occur simultaneously in the same system.