Kinetic Theory

JEE Main level, single correct, medium

51 of 168

Question 51 of 168

Calculate the value of the mean free path (λ)\left(\lambda \right) for oxygen molecules at temperature 27∘C27^{\circ}C and pressure 1.01×105Pa1.01\times {10}^{5}Pa. Assume the molecular diameter 0.3nm0.3nm and the gas is ideal. (k=1.38×10−23JK−1)\left(k=1.38\times {10}^{-23}J{K}^{-1}\right)

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Answer: (D) 102nm102nm

λ=RT2πd2NAP\lambda =\dfrac{RT}{\sqrt{2}\pi {d}^{2}{N}_{A}P}
λ=8.314×3002×3.14×(0.3×10−9)2×6.023×1023×1.01×105\lambda =\dfrac{8.314\times 300}{\sqrt{2}\times 3.14\times {\left(0.3\times {10}^{-9}\right)}^{2}\times 6.023\times {10}^{23}\times 1.01\times {10}^{5}}
λ=102nm\lambda =102nm

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