In thermodynamics, when mass as well as energy are not allowed to cross the boundary, such a system is known as _________.
isolated system
Understanding Thermodynamic System Boundaries
In the field of thermodynamics, a system is defined as a region in space or a quantity of matter chosen for study. Everything external to the system is considered the surroundings. The boundary separates the system from its surroundings. How mass and energy interact with this boundary is crucial for classifying the type of thermodynamic system.
Let's examine the different types of systems based on whether mass and energy are allowed to cross the boundary:
Defining Isolated Systems in Thermodynamics
An isolated system is a system where neither mass nor energy is allowed to cross the boundary. The boundary is completely impermeable to both mass and energy transfer. This means the total mass and total energy within the isolated system remain constant.
Comparing Different System Types
To better understand the isolated system, let's look at other types of thermodynamic systems:
- Closed system: A closed system is one where energy is allowed to cross the boundary, but mass is not. Think of a sealed container filled with gas that is heated or cooled; energy (heat) can enter or leave, but the amount of gas inside remains constant.
- Open system (or Control Volume): An open system allows both mass and energy to cross the boundary. Examples include a pump, a turbine, or even a human body. Mass flows into and out of the system, and energy is also exchanged with the surroundings. A control volume is essentially an open system, typically defined as a fixed region in space through which mass and energy flow.
| System Type | Mass Transfer Across Boundary | Energy Transfer Across Boundary |
|---|---|---|
| Isolated System | No | No |
| Closed System | No | Yes |
| Open System (Control Volume) | Yes | Yes |
Conclusion on the System Definition
The question asks for the type of system where "mass as well as energy are not allowed to cross the boundary". Based on the definitions, this perfectly matches the description of an isolated system. A closed system allows energy transfer, an open system allows both mass and energy transfer, and a control volume is another term for an open system. Therefore, the system where neither mass nor energy crosses the boundary is known as an isolated system.
Important Questions from Thermodynamics System and Processes
- In a polytropic process described by $PV^n = C$, if the polytropic index $n$ is equal to zero, then the process is characterized by constant
Why do particles in liquid water at 0°C have more energy as compared to particles in ice at the same temperature?
Choose the INCORRECT option for the process and its work done (W) and heat transfer (Q) relations.
For a closed system. identify the processes where the following quantities are zero.
1. Heat
2. Work done
3. Internal Energy
Identify the CORRECT statement with respect to the magnitudes of different quantities for different thermodynamic processes.
