Assertion In isothermal process, whole of the heat energy supplied to the body is converted into internal energy.
Reason According to the first laq of thermodynamics,
" "`triangleQ=triangleU+triangleW`

Options

A. Both Assertion and Reason are correct, Reason is the coreect expianation of Assertion
B. Bioth Assertion and Reason are Correct but Reason is not the correct expalnation of Assertion
C. Assetion is correct and Reason is incorrect
D. Assertion is incorrect and Reason is correct

Answer

To solve the given question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding Isothermal Process**:
- An isothermal process is defined as a thermodynamic process in which the temperature of the system remains constant throughout the process.

2. **Internal Energy Change**:
- The change in internal energy (ΔU) for an ideal gas is given by the formula:
\[ \Delta U = nC_V\Delta T \]
- Since the temperature (T) is constant in an isothermal process, we have:
\[ \Delta T = 0 \implies \Delta U = 0 \]

3. **First Law of Thermodynamics**:
- The first law of thermodynamics states:
\[ \Delta Q = \Delta U + \Delta W \]
- Where ΔQ is the heat added to the system, ΔU is the change in internal energy, and ΔW is the work done by the system.

4. **Applying the First Law**:
- Since we established that ΔU = 0 in an isothermal process, we can substitute this into the first law:
\[ \Delta Q = 0 + \Delta W \implies \Delta Q = \Delta W \]
- This means that all the heat energy supplied to the system is converted into work done (ΔW), not into internal energy.

5. **Evaluating the Assertion**:
- The assertion states: "In isothermal process, whole of the heat energy supplied to the body is converted into internal energy."
- Since we found that ΔU = 0, the assertion is incorrect.

6. **Evaluating the Reason**:
- The reason states: "According to the first law of thermodynamics, ΔQ = ΔU + ΔW."
- This statement is indeed correct as it accurately reflects the first law of thermodynamics.

7. **Conclusion**:
- The assertion is incorrect, while the reason is correct. Therefore, the correct option is that the assertion is false and the reason is true.

### Final Answer:
- Assertion: Incorrect
- Reason: Correct