Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is :

Explanation:

• Isochoric process - The isochoric process is defined as the thermodynamic process in which volume is constant. For example, the Ideal Otto cycle.
• Isobaric process - The isobaric process is defined as the thermodynamic process in which pressure is constant. For example, A hot air balloon.
• Isothermal process - The isothermal process is defined as the thermodynamic process in which pressure is constant. For example, A refrigerator is working under this process.
• Adiabatic process -  It is the type of thermodynamic process there is no transfer of the heat or mass between the system and the surroundings is known as the adiabatic process.

In this question, we are given that there are two cylinders A and B of equal capacity which are connected to each via a stop cock.

The entire system is thermally insulated which means that there is no transfer of heat between the system. Therefore, the process is an adiabatic process.

Hence, option (4) is the correct answer.