First law of thermodynamics states that

Options

A. system can do work
B. system has temperature
C. system has pressure
D. heat is form of enrgy

Answer

**Step-by-Step Solution:**

1. **Understanding the First Law of Thermodynamics**:
The First Law of Thermodynamics is a fundamental principle that states that energy cannot be created or destroyed in an isolated system. It can only be transformed from one form to another. This means that the total energy of an isolated system remains constant.

2. **Mathematical Representation**:
The First Law can be mathematically expressed as:
\[ \Delta U = Q - W \]
where:
- \(\Delta U\) = change in internal energy of the system
- \(Q\) = heat added to the system
- \(W\) = work done by the system

3. **Implications of the First Law**:
- If heat \(Q\) is added to the system, it can either increase the internal energy \(\Delta U\) or be used to do work \(W\).
- This means that when heat is supplied to a system, it can lead to an increase in internal energy or be converted into work done by the system.

4. **Evaluating the Options**:
- **Option A**: "A system can do work" - This is correct as per the First Law, since energy can be converted into work.
- **Option B**: "The system has temperature" - This is not a statement derived from the First Law; hence, it is incorrect.
- **Option C**: "Energy can be created or destroyed" - This contradicts the First Law, so it is incorrect.
- **Option D**: "Heat is a form of energy" - This is correct, as heat is indeed a form of energy that can be transferred to or from a system.

5. **Conclusion**:
Based on the above analysis, the correct options that align with the First Law of Thermodynamics are A and D.

**Final Answer**: The First Law of Thermodynamics states that energy cannot be created or destroyed, and it implies that a system can do work (Option A) and that heat is a form of energy (Option D).

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