Answer the following questions in 2-3 sentences each, based on the provided source material.

1. Define what an aerosol is and identify the two fundamental mechanisms of aerosol formation.
2. Explain the conceptual difference between a geometric diameter (like Feret diameter) and an equivalent dynamic properties diameter (like Stokes diameter) for characterizing a non-spherical particle.
3. What is a log-normal distribution, and why is it particularly useful for representing aerosol particle sizes?
4. How does the basis of a particle size distribution (number vs. mass) affect its representation, as illustrated in Figure 1?
5. Describe the relationship between a particle’s terminal settling velocity and its size, and what role the slip coefficient (Cc) plays in this relationship for very small particles.
6. What is Brownian motion, and how does it influence the movement of small aerosol particles compared to gravitational settling?
7. Identify and briefly describe the two primary physical mechanisms for the charging of aerosol particles by gaseous ions.
8. What is Brownian coagulation, and what is its effect on the number concentration and size distribution of an aerosol over time?
9. Explain the Kelvin effect and its significance for the stability of a liquid droplet in the atmosphere.
10. Describe the operating principle of an impactor for sizing aerosol particles and define the term “cut-off size.”