Question

Is the formalism used in this derivation of the first law of thermodynamics correct?

Answer 1

Laws of thermodynamics

The four laws of thermodynamics define fundamental physical quantities (temperature,energy, and entropy) that characterizethermodynamic systems at thermal equilibrium. The laws describe how these quantities behave under various circumstances, and forbid certain phenomena (such as perpetual motion).

The four laws of thermodynamics are:[1][2][3][4][5]

Zeroth law of thermodynamics: If two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other. This law helps define the concept of temperature.First law of thermodynamics: When energy passes, as work, as heat, or with matter, into or out from a system, the system'sinternal energy changes in accord with the law of conservation of energy. Equivalently,perpetual motion machines of the first kind(machines that produce work with no energy input) are impossible