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MHT CET 2021 (24 Sep, Shift 1) · Pressure & Kinetic Energy of a Gas

Pressure & Kinetic Energy of a Gas question from MHT CET 2021 (24 Sep, Shift 1)

Q32MHT CET 2021 · 24 SEP · SHIFT 1Medium

Pressure & Kinetic Energy of a Gas

At what temperature does the average translational kinetic energy of a molecule in a gas becomes equal to kinetic energy of an electron accelerated from rest through potential difference of 'V' volt? (N=N = number of molecules, R=R = gas constant, c=c = electronic charge)

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Answer: (a)

  1. KE of the electron =eV= eV; average KE of a molecule =32kBT= \frac{3}{2}k_BT with kB=RNk_B = \frac{R}{N}.
  2. 32RNT=eV\frac{3}{2}\frac{R}{N}T = eV
  3. T=2eVN3RT = \frac{2eVN}{3R}
  4. So the answer is (a) 2eVN3R\frac{2eVN}{3R}.
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