Define surface energy of liquid -

Options

A. It is defined as frictional force acting between two layer of liquid
B. It is defined as charge flow through conductor in given time
C. It is tendency of liquid surface at rest to shrink in to the minimum surface area possible
D. All of these

Answer

**Step-by-Step Text Solution:**

1. **Understanding Surface Energy:**
Surface energy of a liquid refers to the energy required to increase the surface area of the liquid. It is a measure of the disruption of intermolecular bonds that occurs when the surface of a liquid is increased.

2. **Molecular Behavior:**
In a liquid, molecules are attracted to each other. Molecules in the bulk of the liquid experience equal forces from all directions, resulting in a net force of zero. However, the molecules at the surface are different; they experience a net downward force because they are only partially surrounded by other liquid molecules. This imbalance creates a tendency for the surface molecules to minimize their surface area.

3. **Tendency to Minimize Surface Area:**
The surface of a liquid tends to shrink to achieve the minimum surface area possible. This is due to the cohesive forces between the molecules at the surface, which pull them inward. This phenomenon is what gives rise to the concept of surface tension, which is closely related to surface energy.

4. **Defining Surface Energy:**
Surface energy can be defined quantitatively as the work done per unit area to create a new surface. It is expressed in units of energy per unit area (e.g., Joules per square meter).

5. **Conclusion:**
Therefore, the surface energy of a liquid can be defined as the tendency of the liquid surface at rest to shrink into the minimum surface area possible, which is a result of the attractive forces between the molecules at the surface.

**Final Answer:**
The surface energy of a liquid is defined as the tendency of the liquid surface at rest to shrink into the minimum surface area possible.

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