The net force acting on a molecule inside the liquid is

Options

A. directly upwards at the liquid surface
B. directly inwards at the liquid surface
C. zero
D. infinite

Answer

To determine the net force acting on a molecule inside a liquid, we can follow these steps:

### Step 1: Understand the Environment
A molecule inside a liquid is surrounded by many other molecules. This is crucial because the interactions between these molecules will determine the net force acting on the molecule in question.

**Hint:** Visualize the arrangement of molecules in a liquid and how they interact with each other.

### Step 2: Identify the Forces Acting on the Molecule
The primary force acting on the molecule is the cohesive force, which is the attractive force between similar molecules. Each molecule in the liquid exerts a force on the molecule of interest.

**Hint:** Think about how each neighboring molecule pulls on the central molecule and how these forces are distributed.

### Step 3: Analyze the Direction of Forces
The forces from the surrounding molecules act in all directions. For every attractive force from a molecule in one direction, there is a corresponding attractive force from another molecule in the opposite direction.

**Hint:** Consider drawing a diagram showing the forces acting on the molecule from all sides.

### Step 4: Determine the Net Force
Since the attractive forces from surrounding molecules cancel each other out due to their symmetry, the net force acting on the molecule inside the liquid is zero.

**Hint:** Reflect on the concept of equilibrium and how forces can balance each other out.

### Step 5: Conclusion
The net force acting on a molecule inside a liquid is zero because the cohesive forces from surrounding molecules cancel each other out.

**Final Answer:** The net force acting on a molecule inside a liquid is zero.

---