Efficiency of a heat engine: The fraction of the heat absorbed by an engine which can be converted into work is known as efficiency of the heat engine. Mathematically, Efficiency, η = w / q2 = (T2 - T1) / T2 ……………. (1) As (T2 - T1) / T2 ...

Cyclic process: When a system returns to its original state after completing a series of changes, then it is known that a cycle is completed. This process is known as cyclic process. In a cyclic process the initial and the final state is same. As the ...

Spontaneous processes: A spontaneous process is one in which heat is transferred through a finite temperature. Spontaneous process is also known as irreversible process because these processes take place at very fast rate. All the natural processes are spontaneous processes. Examples of irreversible processes are as follows: 1) Relative ...

Limitations of the first law of thermodynamics are discussed below: 1. No restriction on the direction of the flow of heat: the first law establishes definite relationship between the heat absorbed and the work performed by a system. The first law does not indicate whether heat ...