In thermodynamic processes which of the following statements is not true

Options

A. In an adiabatic process the system is insulated from the surroundings
B. In an isochoric process pressure remains constant
C. In an isothermal process the temperature remains constant
D. In an adiabatic process `PV^(gamma)` = constant

Explanation

To determine which statement is not true regarding thermodynamic processes, we will analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Identify the Statements**:
We have four statements related to thermodynamic processes. We need to evaluate each one to find the incorrect statement.

2. **Evaluate Statement 1**:
- **Statement**: "In an adiabatic process, the system is insulated from the surroundings."
- **Analysis**: This statement is true. In an adiabatic process, there is no heat transfer (Q = 0) between the system and its surroundings, which implies that the system is insulated.

3. **Evaluate Statement 2**:
- **Statement**: "In an isochoric process, the pressure is constant."
- **Analysis**: This statement is false. In an isochoric process, the volume remains constant, not the pressure. The pressure can change while the volume stays the same.

4. **Evaluate Statement 3**:
- **Statement**: "In an isothermal process, the temperature remains constant."
- **Analysis**: This statement is true. In an isothermal process, the temperature of the system does not change throughout the process.

5. **Evaluate Statement 4**:
- **Statement**: "In an adiabatic process, the relation P * V^γ = constant holds."
- **Analysis**: This statement is true. For an adiabatic process involving an ideal gas, the relation between pressure (P) and volume (V) is given by P * V^γ = constant, where γ (gamma) is the heat capacity ratio.

6. **Conclusion**:
After evaluating all statements, we find that the second statement is not true. Therefore, the answer is:
- **Incorrect Statement**: Option 2 (In an isochoric process, the pressure is constant).

### Final Answer:
The statement that is not true is: **Option 2**.

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