The correct answer is option 1) i.e. In an isochoric process pressure remains constant.
CONCEPT:
- Thermodynamic process: It is the change in a system from its initial state of thermodynamic equilibrium to the final state of thermodynamic equilibrium.
- The various types of thermodynamic processes and their relation with pressure( \((\mathrm{P})\) and volume(V) of gas, is as follows:
$\begin{array}{|c|c|}
\hline \begin{array}{l}
\text{Isobaric process}
\end{array} & \begin{array}{l}
\text{- It is a process that takes place under constant pressure.}
\end{array} \\
\hline \begin{array}{l}
\text{Isochoric process}
\end{array} & \begin{array}{l}
\text{- It is a process where the change in volume is zero.} \\
\text{- As the change in volume is zero, the work done is zero.}
\end{array} \\
\hline \begin{array}{l}
\text{Isothermal process}
\end{array} & \begin{array}{l}
\text{- It is a process that takes place under constant temperature.}
\end{array} \\
\hline \begin{array}{l}
\text{Adiabatic process}
\end{array} & \begin{array}{l}
\text{- It is a process in which no heat is exchanged between the} \\
\text{system and the surrounding i.e. the system is insulated.} \\
\text{- It is represented mathematically as } \mathrm{PV}= \text{ constant}
\end{array} \\
\hline
\end{array}$

EXPLANATION:
- An isochoric process is a thermodynamic process that occurs when the change in volume is zero.
- Hence the statement 'In an isochoric process pressure remains constant is not true.