Answer: Number density of molecules.
- A Square root of temperature
- B Number density of molecules
- C Square root of molar mass
- D Gas constant
Correct answer: B. Number density of molecules
Explanation: λ = 1/(√2·n·π·d²), so mean free path decreases as the number density n of molecules increases (e.g., at higher pressure).
Not all gas molecules move at the same speed - the Maxwell-Boltzmann distribution shows the spread, with the most probable speed vp slightly less than the average vavg, which is slightly less than the root-mean-square speed vrms used in the pressure formula.
Concept context
Kinetic theory of gases connects molecular motion to pressure and temperature, explaining gas laws, specific heats, and molecular speeds.