Dust Particles Are Pulverized Rock, Which Has Density 2500 Kg/m³

question 27

Multiple Choice

Dust particles are pulverized rock, which has density 2500 kg/m³. They are approximately spheres 20 μm in diameter. Treating dust as an ideal gas, what is the root-mean-square speed (thermal speed) of a dust particle at 400°C? (The Boltzmann constant is 1.38 × 10^-23 J/K.)

• A) 5.2 × 10^-5 m/s
• B) 1.7 × 10^-5 m/s
• C) 3.0 × 10^-5 m/s
• D) 7.3 × 10^-5 m/s

---

Definitions:

Self-Serving Bias

The common habit of a person taking credit for positive events or outcomes, but blaming outside factors for negative events.

Better-Than-Average Effect

A cognitive bias where individuals overestimate their abilities, qualities, or positive attributes compared to others.

Personal Responsibility

The concept of being accountable for one's actions and accepting the consequences that come with them; underlines the importance of individual action in shaping one's life and society.

Secure Self-Esteem

A form of self-esteem that is stable and resilient to external conditions, reflecting a true and positive self-evaluation.