States of Matter - Result Question 68
####68. The average velocity of gas molecules is $400 m s^{-1}$, find the rms velocity of the gas.
$(2003,2 M)$
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Answer:
Correct Answer: 68. $435 ms^{-1}$
Solution:
- $\frac{u _{av}}{u _{rms}}=\sqrt{\frac{8 R T}{\pi M}}: \sqrt{\frac{3 R T}{M}}=\sqrt{\frac{8}{3 \pi}}$
$\Rightarrow u _{rms}=\sqrt{\frac{3 \pi}{8}} u _{av}=\sqrt{\frac{3 \times 3.14}{8}} \times 400=434 ms^{-1}$
