What does the first law of thermodynamics state?

The first law of thermodynamics, also known as the law of energy conservation, states that energy can neither be created nor destroyed; it can only change form. This principle is fundamental in understanding energy transfer processes within a system. In practical terms, when energy is transformed from one form to another — for example, from potential energy to kinetic energy — the total amount of energy in that system remains constant.

This understanding is crucial in building analysis, where energy use, conservation, and efficiency are key concepts. For instance, in assessing a building's heating and cooling systems, recognizing how energy flows can help improve efficiency and reduce waste.

The other choices present misconceptions about energy conservation. The notion that energy can be created or destroyed suggests a violation of the first law, while claiming that energy remains constant in a closed system doesn't fully capture the essence of energy transformation, which is an integral aspect of the law.