Using P = (1/3) v rms 2 , a gas at pressure 1 10 5 Pa and density 1.25 kg/m 3 has rms speed:

⚛️ Physics · Kinetic Theory · NEET & JEE

Using P = (1/3)ρvrms2, a gas at pressure 1 × 105 Pa and density 1.25 kg/m3 has rms speed:

Answer: 490 m/s.

A ≈245 m/s
B ≈980 m/s
C ≈490 m/s
D ≈360 m/s

Correct answer: C. ≈490 m/s

Explanation: vrms = √(3P/ρ) = √(3×105/1.25) = √240000 ≈ 490 m/s.

Not all gas molecules move at the same speed - the Maxwell-Boltzmann distribution shows the spread, with the most probable speed v_p slightly less than the average v_avg, which is slightly less than the root-mean-square speed v_rms 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.

Read the full Kinetic Theory notes →

Using P = (1/3)&rho;v<sub>rms</sub><sup>2</sup>, a gas at pressure 1 &times; 10<sup>5</sup> Pa and density 1.25 kg/m<sup>3</sup> has rms speed:

Concept context

More Kinetic Theory questions

Using P = (1/3)ρv<sub>rms</sub><sup>2</sup>, a gas at pressure 1 × 10<sup>5</sup> Pa and density 1.25 kg/m<sup>3</sup> has rms speed: