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 question, we need to analyze the assertion and the reason provided in the context of thermodynamics.

### Step-by-step Solution:

1. **Understanding the Assertion**:
- The assertion states: "In an isothermal process, the whole of the heat energy supplied to the body is converted into internal energy."
- An isothermal process is defined as a process that occurs at a constant temperature (T = constant). In this case, the change in temperature (ΔT) is zero.

2. **Understanding the Reason**:
- The reason states: "According to the first law of thermodynamics, ΔQ = ΔU + ΔW."
- The first law of thermodynamics relates the heat added to a system (ΔQ), the change in internal energy (ΔU), and the work done by the system (ΔW).

3. **Applying the First Law of Thermodynamics**:
- For an isothermal process, since the temperature is constant, the internal energy (U) of an ideal gas does not change. Therefore, ΔU = 0.
- Substituting ΔU = 0 into the first law equation gives us:
\[ ΔQ = ΔU + ΔW \implies ΔQ = 0 + ΔW \implies ΔQ = ΔW \]
- This indicates that all the heat energy supplied (ΔQ) is used to do work (ΔW) and not to change the internal energy.

4. **Conclusion**:
- The assertion is incorrect because, in an isothermal process, the heat energy supplied is converted into work, not internal energy.
- The reason is true as it correctly states the first law of thermodynamics.

### Final Answer:
- Assertion: False
- Reason: True
- The assertion is incorrect, and the reason is true but does not explain the assertion.