Which of the following force is utillised in reducing air pollution by removing dust, soot and fly - ash particles from the smoke coming out of chimneys of factories ?

Options

A. magnetic force
B. gravitational force
C. electrostatic force
D. frictional force

Answer

To solve the question regarding which force is utilized in reducing air pollution by removing dust, soot, and fly ash particles from the smoke coming out of chimneys of factories, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Problem**: The question asks about the force that helps in reducing air pollution by removing specific particles (dust, soot, and fly ash) from smoke emitted by factories.

2. **Identifying the Particles**: The particles mentioned (dust, soot, and fly ash) are typically small and can carry electric charges. This is important because certain forces can act on charged particles.

3. **Considering Forces**: We need to think about the types of forces that can act on charged particles. The two main forces that come to mind are gravitational force and electrostatic force.

4. **Electrostatic Force**: The electrostatic force is the force that acts between charged particles. In the context of air pollution control, electrostatic precipitators are used to remove charged particles from smoke. These devices use the principle of electrostatics to attract and collect dust and other particles.

5. **Conclusion**: Since the question specifically mentions the removal of charged particles from smoke, the correct answer is the electrostatic force.

6. **Final Answer**: Therefore, the force utilized in reducing air pollution by removing dust, soot, and fly ash particles from smoke is the **electrostatic force** (Option 3).