The mean free path of molecules of a gas (radius r) is inversely proportional to:
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Question

The mean free path of molecules of a gas (radius r) is inversely proportional to:

G1 Physics · Accepted Answer

Step 1: For a hard-sphere gas, molecular diameter d = 2r. Step 2: Mean free path is λ = 1/(√2 πnd²). Step 3: Substituting d = 2r gives λ = 1/(4√2 πnr²). Step 4: If number density n stays constant, λ ∝ 1/r². Final answer: (B).