When a pressure greater than atmospheric pressure is applied to pure water,its ψw

Options

A. Increases
B. Decreases
C. Becomes zero
D. Remains same

Answer

To solve the question regarding the effect of applying pressure greater than atmospheric pressure on the water potential (ψw) of pure water, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Water Potential**:
Water potential (ψw) is a measure of the potential energy of water in a system. It is influenced by two main factors: solute potential (ψs) and pressure potential (ψp). The formula for water potential is:
\[ \psi_w = \psi_s + \psi_p \]

2. **Identifying the Components**:
- **Solute Potential (ψs)**: This is the effect of solute concentration on water potential. In pure water, there are no solutes present, hence:
\[ \psi_s = 0 \]
- **Pressure Potential (ψp)**: This is the effect of pressure on water potential. When pressure is applied to water, the pressure potential increases.

3. **Applying Pressure**:
When pressure greater than atmospheric pressure is applied to pure water, the pressure potential (ψp) increases. Since we established that:
\[ \psi_s = 0 \]
The water potential now becomes:
\[ \psi_w = \psi_s + \psi_p = 0 + \psi_p = \psi_p \]

4. **Conclusion**:
As the pressure potential increases due to the applied pressure, the water potential (ψw) also increases. Therefore, when a pressure greater than atmospheric pressure is applied to pure water, its water potential (ψw) increases.

### Final Answer:
When a pressure greater than atmospheric pressure is applied to pure water, its water potential (ψw) increases.