A body cools in a surrounding of constant temperature `30^@C` Its heat capacity is `2 J//^(@)C`. Initial temperature of cooling is valid. The body of mass 1 kg cools to `38^@C` in 10 min
When the body temperature has reached `38^@C`, it is heated again so that it reaches `40^@C` in 10 min. The heat required from a heater by the body is

Options

A. 3.6 J
B. 0.364 J
C. 8 J
D. 4 J

Explanation

To solve the problem, we need to calculate the heat required from a heater to raise the temperature of the body from 38°C to 40°C.

### Step-by-Step Solution:

1. **Identify the given data:**
- Initial temperature when heating starts, \( T_1 = 38°C \)
- Final temperature after heating, \( T_2 = 40°C \)
- Heat capacity of the body, \( C = 2 \, \text{J/°C} \)
- Mass of the body, \( m = 1 \, \text{kg} \)

2. **Calculate the change in temperature (\( \Delta T \)):**
\[ \Delta T = T_2 - T_1 = 40°C - 38°C = 2°C \]

3. **Use the formula for heat required (\( Q \)):**
The heat required to change the temperature of a body can be calculated using the formula:
\[ Q = m \cdot C \cdot \Delta T \]
Here, since we are given the heat capacity directly, we can use it as:
\[ Q = C \cdot \Delta T \]

4. **Substitute the values into the formula:**
\[ Q = 2 \, \text{J/°C} \cdot 2°C = 4 \, \text{J} \]

5. **Conclusion:**
The heat required from the heater to raise the temperature of the body from 38°C to 40°C is \( 4 \, \text{J} \).

### Final Answer:
The heat required from a heater by the body is **4 Joules**.

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