An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic, isothermal, isobaric and isochoric. The curve which represents the adiabatic process among 1, 2, 3 and 4 is:

Concept:

• Thermodynamics is the branch of science which deals with the study of energy transfers in a system or between the systems in the form of heat, work, and temperature. 
• There are four types of thermodynamic processes:

Isobaric process: The process in which pressure of the system remains constant is called as isobaric process.

Isochoric process: The process in which volume of the system remains constant is called as Isochoric process.

Isothermal process: The process in which temperature of the system remains constant is called as Isothermal process.

Adiabatic process: The process in which there is no exchange of heat between system and surroundings is called as Adiabatic process.

Explanation:

The curve and respective process represented by them is

1: Isochoric

2: Adiabatic

3: Isothermal

4: Isobaric

Hence option (3) is the correct answer.