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JEE Main 2023 (11 Apr, Shift 2) · Molecular Speeds & Maxwell Distribution

Molecular Speeds & Maxwell Distribution question from JEE Main 2023 (11 Apr, Shift 2)

Q45JEE Main 2023 · 11 APR · SHIFT 2Medium

Molecular Speeds & Maxwell Distribution

The root mean square speed of molecules of nitrogen gas at 27∘C27^\circ\text{C} is approximately: (Given mass of a nitrogen molecule =4.6×10−26 kg= 4.6 \times 10^{-26}\text{ kg} and take Boltzmann constant kB=1.4×10−23 J K−1k_B = 1.4 \times 10^{-23}\text{ J K}^{-1})

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Answer: (d)

  1. vrms=3kBTmv_{rms} = \sqrt{\frac{3k_BT}{m}} with T=300 KT = 300\text{ K}
  2. vrms=3×1.4×10−23×3004.6×10−26=2.74×105v_{rms} = \sqrt{\frac{3\times1.4\times10^{-23}\times300}{4.6\times10^{-26}}} = \sqrt{2.74\times10^5}
  3. vrms≈523 m/sv_{rms} \approx 523\text{ m/s}
  4. So the answer is (d) 523 m/s.
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