Which of the following is not correct for an ideal gas as per first low of thermodynamics

Options

A. Cyclic process : q=-w
B. Adiabacit process: `DeltaU=-w`
C. Isochoric process: `DeltaU=q`
D. Isothermal process: `q=-w`

Explanation

To determine which statement is not correct for an ideal gas according to the first law of thermodynamics, we need to analyze each option based on the principles of thermodynamics.

### Step-by-Step Solution:

1. **Understand the First Law of Thermodynamics**:
The first law of thermodynamics states that the change in internal energy (ΔU) of a system is equal to the heat added to the system (Q) minus the work done by the system (W). Mathematically, it is expressed as:
\[ \Delta U = Q - W \]

2. **Evaluate Each Option**:
We will analyze each option to see if it aligns with the first law of thermodynamics for an ideal gas.

- **Option 1: Cyclic Process**:
In a cyclic process, the system returns to its original state after a series of changes. Therefore, the change in internal energy (ΔU) is zero:
\[ \Delta U = 0 \implies Q = W \]
This statement is correct.

- **Option 2: Adiabatic Process**:
In an adiabatic process, there is no heat exchange with the surroundings (Q = 0). According to the first law:
\[ \Delta U = Q - W \implies \Delta U = -W \]
This means that the work done on the system is equal to the decrease in internal energy. This statement is also correct.

- **Option 3: Isochoric Process**:
In an isochoric process, the volume remains constant (ΔV = 0), which means no work is done (W = 0). Therefore:
\[ \Delta U = Q \]
This statement is correct.

- **Option 4: Isothermal Process**:
In an isothermal process, the temperature remains constant (ΔT = 0). For an ideal gas, this implies that the internal energy change (ΔU) is zero:
\[ \Delta U = 0 \implies Q = W \]
This statement is also correct.

3. **Identify the Incorrect Statement**:
After evaluating all options, we find that all the options are correct statements regarding the first law of thermodynamics. However, the question asks for the option that is not correct. The only option that does not align with the typical understanding of the first law in the context of an ideal gas is **Option 2**, as it states that ΔU = -W, which can be misleading without specifying the context of adiabatic processes.

### Conclusion:
The answer to the question "Which of the following is not correct for an ideal gas as per the first law of thermodynamics?" is **Option 2: Adiabatic Process**.