A number of small drops of mercury adiabatically coalesce to form a single drop. The temperature of the drop will

Options

A. increase
B. remain same
C. decrease
D. depend on size

Answer

To solve the question regarding the temperature change of a drop of mercury formed by the adiabatic coalescence of smaller drops, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Process**:
- We start with several small drops of mercury. When these drops coalesce to form a larger drop, we need to consider the nature of this process. The term "adiabatically" indicates that no heat is exchanged with the surroundings during this process.

**Hint**: Remember that "adiabatic" means no heat transfer occurs.

2. **Potential Energy Consideration**:
- When small drops coalesce, they release potential energy that was stored in the form of surface energy. The surface energy is higher for smaller drops due to their larger surface area relative to volume. When these drops combine, the surface area decreases, and thus the potential energy is converted.

**Hint**: Think about how surface area affects energy in small versus large drops.

3. **Energy Release and Temperature Change**:
- Since the process is adiabatic and involves the release of potential energy, this energy is converted into internal energy of the larger drop. As a result, the temperature of the larger drop will increase because the internal energy of a substance is related to its temperature.

**Hint**: Consider how energy conversion affects temperature in a closed system.

4. **Conclusion**:
- Therefore, the temperature of the newly formed larger drop of mercury will increase as a result of the adiabatic coalescence of the smaller drops.

**Hint**: Summarize the findings: what happens to temperature when energy is released in an adiabatic process?

### Final Answer:
The temperature of the drop will **increase**.