⚛️ Physics · Kinetic Theory · NEET & JEE

Two gases, hydrogen (M=2 g/mol) and oxygen (M=32 g/mol), are at the same temperature. The ratio of their rms speeds (vH2 / vO2) is:

Answer: 4.

A 4
B 16
C 2
D 8

Correct answer: A. 4

Explanation: vrms ∝ 1/√M, so ratio = √(MO2/MH2) = √(32/2) = √16 = 4.

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.

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Two gases, hydrogen (M=2 g/mol) and oxygen (M=32 g/mol), are at the same temperature. The ratio of their rms speeds (v<sub>H</sub><sub>2</sub> / v<sub>O</sub><sub>2</sub>) is:

Concept context

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