A calorimeter takes `200 cal` of heat to rise its temperature through `10^@C`. Its water equivalent in `gm` is

Options

A. `2`
B. `10`
C. `20`
D. `40`

Explanation

To find the water equivalent of the calorimeter, we can use the formula that relates heat absorbed, mass, specific heat, and temperature change. Here are the steps to solve the problem:

### Step-by-Step Solution:

1. **Understand the Given Information**:
- Heat absorbed by the calorimeter, \( Q = 200 \) calories.
- Temperature change, \( \Delta T = 10^\circ C \).

2. **Use the Formula for Heat Transfer**:
The formula for heat transfer is given by:
\[ Q = m \cdot s \cdot \Delta T \]
where:
- \( Q \) is the heat absorbed (in calories),
- \( m \) is the mass (in grams),
- \( s \) is the specific heat capacity (for water, \( s = 1 \) calorie/g°C),
- \( \Delta T \) is the change in temperature (in °C).

3. **Substitute the Known Values**:
Since we are considering the water equivalent, we can substitute the known values into the formula:
\[ 200 = m \cdot 1 \cdot 10 \]

4. **Simplify the Equation**:
This simplifies to:
\[ 200 = 10m \]

5. **Solve for \( m \)**:
To find \( m \), divide both sides by 10:
\[ m = \frac{200}{10} = 20 \text{ grams} \]

6. **Conclusion**:
The water equivalent of the calorimeter is \( 20 \) grams.

### Final Answer:
The water equivalent of the calorimeter is **20 grams**.