## Thermodynamic Process:

A closed thermodynamic system, a system having a fixed mass can be described completely by three of its properties – volume (V), pressure (p), and temperature (T). All other properties of the system depend on and therefore are functions of V, p, and T.

When none of the three properties of a system – volume, pressure, or temperature – changes with time, the system is said to be in an **equilibrium state**.

Moreover, volume, pressure, and temperature are related among themselves by an equation of state. Thus, if two of them are known, the third can be calculated using that equation of state. Hence, **there are only Independent properties for a closed thermodynamic system**.

## Types of Thermodynamic Process:

Let a system be initially at an equilibrium state A. Now, if the system exchanges energy, in the form of work or heat. With its surroundings, then the values of V, p, and T would change, in general. So, the system would deviate from the state A. But eventually, when the energy exchange stops, the system would attain a new equilibrium state, say B.

The transition of a system from an initial state A to a final state B is known as Thermodynamic Process. It is usually denoted as A → B. There are mainly four types of thermodynamic process:

**1. Isochoric Process:** The volume of a system remains constant in this process. But, both pressure and temperature undergo some changes.

**2. Isobaric Process:** Here, p remains constant and V and T change their values.

**3. Isothermal Process:** T is a constant, whereas there are changes in V and p.

**4. Adiabatic Process:** The heat exchange between the system and its surroundings remains zero. There are changes in all of V, p, and T.