Question

What are the first three laws of thermodynamics?

Answer 1

Hint:Thermodynamics is a branch of physics that investigates the links between heat, work, and temperature, as well as their interactions with energy, radiation, and the physical properties of matter. The behaviour of these values is governed by the four thermodynamic principles, which provide a quantitative description utilising quantifiable macroscopic physical features but can be defined in terms of tiny constituents by statistical mechanics.

Complete step by step answer:
First law: The first law of thermodynamics is a thermodynamics-adapted version of the law of conservation of energy. In principle, the conservation law asserts that an isolated system's total energy remains constant; energy can be transferred from one form to another, but it cannot be created or destroyed.
The first law states that the change in internal energy of the system \[\left( {\vartriangle {U_{system}}} \right)\]is equal to the difference between the heat provided to the system \[\left( Q \right)\]and the work \[\left( W \right)\]done by the system on its surroundings in a closed system (i.e. there is no transfer of matter into or out of the system).
$\Delta {U_{{\text{system}}}} = Q - W.$
Second Law: When two initially isolated systems in different but close regions of space, each in thermodynamic equilibrium with itself but not necessarily with each other, are allowed to interact, they eventually establish mutual thermodynamic equilibrium. The overall entropy of the final combination is less than or equal to the sum of the entropies of the initially isolated systems. Equality happens when all of the intense variables (temperature, pressure) in the two original systems are equal; the resulting system then has the same values.
Third Law: At \[0\] degrees Celsius, the system must be in the ground state, which has the least amount of thermal energy. The system's residual entropy is the constant value of entropy at this point. It's worth noting that, with the exception of non-crystalline substances, a system's residual entropy is usually near to zero. It only approaches \[0\] when the system has a single ground state. Because each microstate is believed to have the same probability of occurring, macroscopic states with fewer microstates have a lower probability of occurring. According to Boltzmann principle entropy is proportional to the number of possible microstates.

Note: Thermal equilibrium is defined by the zeroth law of thermodynamics, which also serves as a foundation for the concept of temperature: If two systems are in thermal equilibrium with a third system, they are also in thermal equilibrium with each other.