A cooling curve is plotted between the temperature of a hot body and time. Which of the following is not true for the cooling curve?

Options

A. Cooling is faster from a calorimeter having a larger surface area than a smaller one.
B. Cooling is faster from a calorimeter painted black from outside than that from a polished surfaced calorimeter.
C. Cooling is faster from a copper calorimeter than from a steel calorimeter.
D. The rate of cooling remains same throughout the experiment. Hence the graph is a striagth line

Answer

To solve the question regarding the cooling curve, let's analyze the statements one by one to determine which one is not true.

### Step-by-step Solution:

1. **Understanding the Cooling Curve**:
A cooling curve is a graph that represents the temperature of a hot body over time as it cools down. The rate of cooling is influenced by various factors, including surface area, emissivity, and specific heat capacity.

2. **Analyzing the Statements**:
- **Statement A**: "Cooling is faster from a calorimeter having a larger surface area."
- This statement is true because a larger surface area allows for more heat to be lost to the surroundings, thus increasing the rate of cooling.

- **Statement B**: "Cooling is faster for a calorimeter painted black from outside than for a polished surface."
- This statement is also true. A black surface has a higher emissivity, which means it can radiate heat more effectively than a polished surface, leading to faster cooling.

- **Statement C**: "Cooling is faster from a copper calorimeter than from a steel calorimeter."
- This statement is true as well. Copper has a lower specific heat capacity compared to steel, which means it can lose heat more quickly, resulting in faster cooling.

- **Statement D**: "The rate of cooling remains the same throughout the experiment."
- This statement is not true. The rate of cooling changes over time; it is generally faster when the temperature difference between the body and its surroundings is greater. As the temperature of the body decreases, the rate of cooling also decreases.

3. **Conclusion**:
The statement that is not true for the cooling curve is **Statement D**: "The rate of cooling remains the same throughout the experiment."

### Final Answer:
The statement that is not true for the cooling curve is **D**: "The rate of cooling remains the same throughout the experiment."