Answer: (1/3)ρv rms ².
- A (1/3)ρv<sub>rms</sub>²
- B (2/3)ρv<sub>rms</sub>²
- C ρv<sub>rms</sub>²
- D (1/2)ρv<sub>rms</sub>²
Correct answer: A. (1/3)ρv<sub>rms</sub>²
Explanation: Kinetic theory gives the result P = (1/3)ρv<sub>rms</sub>², where ρ is the density of the gas and v<sub>rms</sub> its root mean square speed.
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.