What Happens At The Time Of A Reversible Process?

There are several categories of the division of thermodynamic processes. One among them is irreversible and reversible. Here, irreversible processes are all processes that cannot be reversed once they take place. Similarly, on the other hand, a Reversible process is any process that can be reversed without making any significant changes in the universe’s entropy. Moreover, unlike irreversible processes, reversible processes do not occur naturally, and hence, they take place hypothetically. There are many other aspects of reversible processes. Let’s dive directly into details. 

Aspects of Reversible Process

In a nutshell, a Reversible process is a sort of process where any thermodynamic process gets reversed in such a way that the system and surroundings both retain their initial state without any additional charges in the universe. This process does not occur naturally, though it takes place only when surroundings are in thermodynamic equilibrium. However, there are chances that surroundings or objects undergo tiny shifts. Moreover, this type of process does not affect the universe’s entropy because it occurs at an infinitesimal scale.

Characteristics that can be seen during the process

• If the environment is working on the system, a minimum quantity of effort is required for a particular state change if the process is reversible.
• It is gradually withdrawn off equilibrium without causing any major changes in internal temperature, pressure, or velocity changes. Further, they also undergo a series of other equilibrium states.
• They can be reversed at any moment if they’ve taken place externally.
• The surroundings extract the most work achievable from the system with a particular state change.

Components of Reversible Process 

Two essential components result in the reversible process. In the absence of them, the process becomes irreversible. They are as follows: 

1.Dissipative force must be absent

Dissipative forces can be regarded as the forces which drive away from the energy from reactions or processes. Moreover, it is the manner by which energy gets transferred across systems and surroundings. Friction is an example of Dissipative force, and it obstructs the reversibility of the process by driving away the energy from the surroundings. When negligible or absent friction, the process easily gets reversed with less heat. On the other hand, in the presence of such (dissipative) forces, more heat is required by the surroundings to restore their initial state. As a result, it often results in a positive value of entropy which indicates Irreversibility. 

2.The process should occur in an infinitely short time.

Anytime the reversible process is taking place, it must take infinitely slowly due to an infinitesimal gradient. It is due to friction, and similar hysteresis features are necessary for reversible processes. If it takes place readily, the system would be set up with pressure changes and limited temperature gradients, leading to irreversible loss and heat flow.

Process of different types of Reversible Processes

• Internally reversible process

Here, no irreversibility arises inside the system. A system travels through a sequence of equilibrium states in these operations, and whenever the cycle reverses, the system travels through the exact same equilibrium points on its way back to its initial condition.

• Externally reversible process

It is converse of internally reversible processes. There are no irreversibilities outside the system limits during an externally reversible process. If the area of contact between both the system and the reservoir is at an exact temperature, heat flow across them represents an externally reversible process.

Examples of Reversible Process

• The temperature of a block of ice inside a closed box will vary very slightly, and the ice will melt after a short time.
• Gradual and adiabatical compression of air.
• Pushing an object on a frictionless surface.

Conclusion

From all the above, we learned aspects of the reversible process and the manner in which the reversible process takes place. During the process, the system and surroundings do not have any dissipating forces like friction. Also, they take place in an infinitely short time since any ready processing will make the process irreversible. Reversible processes do not take place naturally. Hence they are considered hypothetical processes which are processed manually. Moreover, aside from components, there are two types of reversible processes, internal and external. The internally reversible process is where the reversible process takes place inside the system only. External is the opposite; here, the process takes place outside the system only, in the surroundings. The freezing of melted ice is an example of a Reversible process.