In the absence of any external force, liquid drop are sperical in shape. It is due to

Options

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

Answer

To solve the question regarding why liquid drops are spherical in shape in the absence of any external force, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept of Surface Tension**:
- Surface tension is a property of liquids that causes the surface to behave like a stretched elastic membrane. It arises due to the cohesive forces between liquid molecules.

2. **Energy Minimization**:
- Any physical system tends to minimize its energy. For a liquid drop, the relevant energy is the surface energy, which is proportional to the surface area of the drop.

3. **Surface Energy Calculation**:
- The surface energy (U) can be expressed as:
\[ U = \text{Surface Tension} \times \text{Area} \]
- This implies that the energy is minimized when the surface area is minimized.

4. **Comparing Shapes**:
- For a given volume of liquid, different shapes will have different surface areas. Among all possible shapes, the sphere has the smallest surface area for a given volume.

5. **Conclusion**:
- Therefore, in the absence of external forces, a liquid drop will assume a spherical shape to minimize its surface area and, consequently, its surface energy.

### Final Answer:
The spherical shape of liquid drops in the absence of external forces is due to **surface tension**, which causes the liquid to minimize its surface area and energy.

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