Your interviewer will likely ask you knowledge-based questions to understand how well you are able to explain concepts to others. Be prepared for questions like this one by practicing a few possibilities ahead of time. In this case, the Carnot cycle generally describes the conversion of heat into work via four ideal thermodynamic phases. It is most often used in relation to an engine, specifically an internal combustion engine. However, it can also be applied to refrigeration systems. The cycle consists of two phases of compression and two phases of expansion, one of which is isothermal (same temperature) while the other is adiabatic (no heat transfer) and reversible (no friction). This question may be asked to gauge your familiarity with thermodynamics, which may or may not be directly relevant for the role.