The S.I. unit of heat energy is

Options

A. Joule
B. Calorie
C. kilo calorie
D. none of these

Explanation

To determine the S.I. unit of heat energy, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Heat and Energy**:
- Heat is a form of energy that is transferred between systems or objects with different temperatures. Energy, in general, is the capacity to do work.

2. **Identifying the Relationship**:
- Heat and energy are often used interchangeably in physics, as heat is a type of energy.

3. **S.I. Units**:
- The International System of Units (S.I.) provides standard units for measuring various physical quantities.

4. **Finding the Unit for Energy**:
- The S.I. unit for energy is the Joule, which is represented by the symbol 'J'.

5. **Conclusion**:
- Therefore, the S.I. unit of heat energy is Joules (J).

### Final Answer:
The S.I. unit of heat energy is Joules (J).

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