Answer: 2v.
- A √2 v
- B 2v
- C 4v
- D v
Correct answer: B. 2v
Explanation: v<sub>rms</sub> ∝ √T; T goes from 300 K to 1200 K (4×), so speed becomes √4 = 2v.
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.