What occurs during the expansion process in a refrigeration cycle?

During the expansion process in a refrigeration cycle, the refrigerant undergoes a significant drop in pressure and temperature as it transitions from the high-pressure liquid state to a low-pressure mixture of vapor and liquid. This process usually occurs in an expansion valve or a similar device, where the refrigerant is allowed to expand freely.

When the refrigerant expands, it does work on its surroundings, which results in a decrease in internal energy. As a direct result of this energy change, the temperature of the refrigerant drops. This cooling effect is essential as it allows the refrigerant to absorb heat from the environment during the subsequent evaporation process, making it effective in the refrigeration cycle.

In summary, option A accurately describes the scenario of the expansion process, highlighting the critical decrease in both pressure and temperature of the refrigerant.