MCQ Detailed View

In thermodynamics, the definite area or space where a thermodynamic process takes place is called a thermodynamic system. A system is a specifically defined region of space or a quantity of matter that we choose to study. Everything outside this boundary is called the surroundings. The imaginary surface that separates the system from the surroundings is known as the boundary.

Thermodynamic systems can be classified into three main types:

1. 
   

   Open system – A system that allows both matter and energy to cross its boundary. For example, boiling water in an open pot allows steam (matter) and heat (energy) to escape.

   
   


2. 
   

   Closed system – A system where only energy can cross the boundary but not matter. For instance, water in a sealed container can exchange heat with the environment but the mass of water remains constant.

   
   


3. 
   

   Isolated system – A system that does not exchange either matter or energy with its surroundings. A perfectly insulated thermos flask is an approximate example.

   
   

The study of thermodynamic systems is essential because it allows scientists and engineers to apply the laws of thermodynamics. These laws explain how energy is conserved, transferred, and converted from one form to another. For example, in an internal combustion engine, the thermodynamic system is the space inside the cylinder where fuel and air react, producing heat and mechanical work.

It is important to differentiate a thermodynamic system from related terms. A thermodynamic process refers to the actual change that occurs in the system (such as heating, compression, or expansion). A thermodynamic cycle is a series of processes that return a system to its initial state, such as the Carnot cycle or the Rankine cycle. A thermodynamic law is a fundamental principle governing these processes, such as the first or second law of thermodynamics.

Therefore, the correct answer is thermodynamic system, as it represents the definite area or space in which thermodynamic changes occur and are studied.