How much work can be done by `100` calories of heat?

Options

A. 100 J
B. 420 J
C. 42 J
D. 4200 J

Explanation

To find out how much work can be done by 100 calories of heat, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Units**:
- We know that calories and joules are both units of energy.
- Specifically, 1 calorie is defined as the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius.

2. **Conversion Factor**:
- The conversion between calories and joules is given as:
\[ 1 \text{ calorie} = 4.2 \text{ joules} \]

3. **Calculate Total Joules for 100 Calories**:
- To convert 100 calories to joules, we multiply by the conversion factor:
\[ 100 \text{ calories} = 100 \times 4.2 \text{ joules} \]

4. **Perform the Calculation**:
- Now, we calculate:
\[ 100 \times 4.2 = 420 \text{ joules} \]

5. **Conclusion**:
- Therefore, the amount of work that can be done by 100 calories of heat is:
\[ \text{Work} = 420 \text{ joules} \]

### Final Answer:
The work that can be done by 100 calories of heat is **420 joules**.

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