The thermal capacity of a body is 80 cal , then its water equivalent is

Options

A. 80 cal / gm
B. 8 gm
C. 80 gm
D. 80 kg

Answer

To find the water equivalent of a body with a thermal capacity of 80 cal, we can follow these steps:

### Step-by-step Solution:

1. **Understand the Definitions**:
- **Thermal Capacity (H)**: The amount of heat required to change the temperature of a body by 1 Kelvin (or 1 degree Celsius).
- **Water Equivalent (M)**: The mass of water that would absorb the same amount of heat as the body for the same temperature change.

2. **Given Data**:
- Thermal Capacity (H) = 80 cal/K.

3. **Specific Heat of Water**:
- The specific heat (S) of water is known to be 1 cal/g/K.

4. **Using the Formula**:
- The relationship between thermal capacity and water equivalent can be expressed as:
\[ H = M \times S \]
- Where:
- \( H \) = Thermal Capacity (80 cal/K)
- \( M \) = Water Equivalent (in grams)
- \( S \) = Specific Heat of Water (1 cal/g/K)

5. **Substituting Values**:
- Substitute the known values into the equation:
\[ 80 \text{ cal/K} = M \times 1 \text{ cal/g/K} \]

6. **Solving for Water Equivalent (M)**:
- Rearranging the equation gives:
\[ M = \frac{80 \text{ cal/K}}{1 \text{ cal/g/K}} = 80 \text{ g} \]

7. **Conclusion**:
- The water equivalent of the body is 80 grams.

### Final Answer:
The water equivalent of the body is **80 grams**.

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