Which of the following statements are true about the First Law of Thermodynamics?
A Energy cannot be created or destroyed, only transferred or transformed.
B The total energy of an isolated system remains constant.
C The First Law implies that the efficiency of energy conversion is always 100%.
D It is also known as the law of conservation of energy.
The correct answer and explanation is:
The correct answers are A, B, and D.
Explanation:
The First Law of Thermodynamics is a fundamental principle that asserts that energy cannot be created or destroyed, only transferred or transformed from one form to another. This is encapsulated in statement A, which correctly describes the law as the conservation of energy.
Statement B is also true, as the First Law suggests that the total energy in an isolated system remains constant. While energy can change forms (e.g., from kinetic to thermal energy), the overall quantity of energy stays unchanged. This is why the law is often referred to as the conservation of energy, a term highlighted in statement D.
Statement C is false. The First Law does not imply that energy conversion is always 100% efficient. In real-world systems, energy is often lost in forms like heat due to friction, resistance, or inefficiency in mechanical processes. This is governed by the Second Law of Thermodynamics, which states that energy conversions often result in entropy, or disorder, which limits efficiency.
The First Law is crucial for understanding how energy is conserved across different processes. It plays a central role in fields like physics, chemistry, and engineering, where it governs the behavior of systems, from engines to biological processes. In essence, while energy may change forms, it is never lost—only transformed—making it a cornerstone principle for understanding how the universe operates.
Thus, statements A, B, and D accurately represent the First Law of Thermodynamics, while C is incorrect.