Zero energy cool chamber operates on the principle of

Correct option is B

Zero energy cool chamber works on the principle of evaporative cooling, where evaporation of water absorbs heat from surroundings. When water present on the surface of the chamber evaporates, it causes reduction in temperature inside the chamber. This cooling effect helps in maintaining lower temperature and higher relative humidity without using electricity. Therefore, the operating principle of zero energy cool chamber is evaporative cooling.
Information booster: Zero energy cool chambers are mainly used for short-term storage of fruits and vegetables at farm level. They are especially useful for small and marginal farmers in rural areas where electricity is not available. The system helps in reducing post-harvest losses by slowing down respiration and transpiration. It is an eco-friendly and low-cost storage technology developed for sustainable agriculture.
Why other options are incorrect: (a) Second law of thermodynamics explains energy transfer but does not describe the cooling mechanism used here. (c) Boyle’s law relates pressure and volume of gases and is not applicable to cooling chambers. (d) Charles’s law relates temperature and volume of gases, not evaporative cooling.