An Introduction to Modern Astrophysics · Problem 9.6
The Interiors of Stars — Carroll & Ostlie
Physics — Astrophysics · mean-free-path-nitrogen
Problem
Using the root-mean-square speed, vrms, estimate the mean free path of the nitrogen molecules in your classroom at room temperature (300 K). What is the average time between collisions? Take the radius of a nitrogen molecule to be 0.1 nm and the density of air to be 1.2 kg m−3. A nitrogen molecule contains 28 nucleons (protons and neutrons).