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JEE Main 2023 (6 Apr, Shift 1) · Mean Free Path & Real Gases

Mean Free Path & Real Gases question from JEE Main 2023 (6 Apr, Shift 1)

Q12JEE Main 2023 · 6 APR · SHIFT 1Medium

Mean Free Path & Real Gases

The number of air molecules per cm3^{3} increased from 3×10193 \times 10^{19} to 12×101912 \times 10^{19}. The ratio of collision frequency of air molecules before and after the increase in number respectively is:

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Answer: (b)

  1. Collision frequency f=2 nπd2vˉ∝nf = \sqrt{2}\,n\pi d^2\bar v \propto n (same TT, same gas).
  2. f1f2=3×101912×1019=0.25\dfrac{f_1}{f_2} = \dfrac{3\times10^{19}}{12\times10^{19}} = 0.25
  3. So the answer is (b) 0.25.
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