When stirred with a spoon and left, water comes to rest after some time. It occurs due to

Options

A. a. Surface tension
B. b. Energy conservation
C. c. Pressure
D. d. Viscosity

Answer

To solve the question "When stirred with a spoon and left, water comes to rest after some time. It occurs due to:", we need to analyze the situation and the options provided.

### Step-by-Step Solution:

1. **Understanding the Scenario**:
- When water is stirred with a spoon, it gains kinetic energy and starts moving. Once the stirring stops, the water begins to slow down and eventually comes to rest.

2. **Identifying the Forces at Play**:
- The motion of the water is affected by various forces. The main force that opposes the motion of the water is viscosity.

3. **Defining Viscosity**:
- Viscosity is a measure of a fluid's resistance to flow. It represents the internal friction within the fluid that resists motion. In simpler terms, it is the reason why fluids do not flow indefinitely once disturbed.

4. **Analyzing the Options**:
- **Surface Tension**: This is the elastic tendency of a fluid surface which makes it acquire the least surface area. It does not primarily affect the motion of the bulk fluid.
- **Energy Conservation**: While energy conservation principles apply, they do not directly explain why the water comes to rest.
- **Pressure**: Changes in pressure can affect fluid motion, but they are not the primary reason for the water coming to rest.
- **Viscosity**: This is the correct answer as it directly relates to the internal friction that opposes the motion of the water.

5. **Conclusion**:
- Therefore, the water comes to rest due to viscosity, as it acts as a frictional force that opposes the motion of the water.

### Final Answer:
The water comes to rest after being stirred due to **viscosity**.

---