Easy MCQ +4 / -1 PYQ · JEE Mains 2021

if the rms speed of oxygen molecules at 0$^\circ$C is 160 m/s, find the rms speed of hydrogen molecules at 0$^\circ$C.

  1. A 640 m/s Correct answer
  2. B 40 m/s
  3. C 80 m/s
  4. D 332 m/s

Solution

${V_{rms}} = \sqrt {{{3KT} \over M}}$<br><br>$${{{{({V_{rms}})}_{{O_2}}}} \over {{{({V_{rms}})}_{{H_2}}}}} = \sqrt {{{{M_{{H_2}}}} \over {{M_{{O_2}}}}}} = \sqrt {{2 \over {32}}} $$<br><br>${({V_{rms}})_{{H_2}}} = 4 \times {({V_{rms}})_{{O_2}}}$<br><br>$= 4 \times 160$<br><br>$= 640$ m/s

About this question

Subject: Physics · Chapter: Thermodynamics · Topic: Zeroth and First Law

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