# Carnot Cycle: Reversibility Under Constant External Pressure

• asap9993
In summary, the Carnot Cycle is a thermodynamic cycle that describes the most efficient way to convert heat energy into mechanical work. It operates between two temperature reservoirs and consists of four reversible processes. The principle of reversibility ensures that the system can be brought back to its original state without energy loss. Constant external pressure is necessary for the isothermal processes, which allow for maximum efficiency. However, the Carnot Cycle has limitations such as not accounting for real-world factors and making it impossible to achieve 100% efficiency in practical applications.

#### asap9993

An ideal, monatomic gas is going through a 4 step Carnot cycle. Step 1 is an adiabatic expansion. Step 2 is an isothermal expansion. Step 3 is an adiabatic compression. Step 4 is an isothermal compression. The whole cycle is reversible. My question is how would the cycle change if step 1 is done against constant external pressure. Would the work be different?

What would be the endpoint of that isobaric expansion? ehild

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## 1. What is the Carnot Cycle?

The Carnot Cycle is a thermodynamic cycle that describes the most efficient way to convert heat energy into mechanical work. It consists of four reversible processes: isothermal expansion, adiabatic expansion, isothermal compression, and adiabatic compression.

## 2. What is the principle of reversibility in the Carnot Cycle?

The principle of reversibility states that every process in the Carnot Cycle can be reversed without any loss of energy. This means that the system can be brought back to its original state by following the reverse path of the cycle.

## 3. How does the Carnot Cycle achieve maximum efficiency?

The Carnot Cycle achieves maximum efficiency by operating between two temperature reservoirs, a hot reservoir and a cold reservoir. During the isothermal expansion and compression processes, the system is in thermal equilibrium with the hot and cold reservoirs, respectively. This ensures that the system operates at the maximum temperature difference, resulting in maximum efficiency.

## 4. What is the role of constant external pressure in the Carnot Cycle?

Constant external pressure is necessary in the Carnot Cycle to maintain the isothermal processes. This ensures that the system remains in thermal equilibrium with the hot and cold reservoirs, allowing for maximum efficiency.

## 5. What are the limitations of the Carnot Cycle?

The Carnot Cycle is an idealized model and does not account for real-world factors such as friction, heat loss, and non-reversible processes. It also assumes that the system operates in a vacuum and does not consider the time required for the processes to occur. These limitations make it impossible to achieve 100% efficiency in practical applications.