States of Matter - Result Question 28
####28. Root mean square velocity of a gas molecule is proportional to
(a) $m^{1 / 2}$
(b) $m^{0}$
(c) $m^{-1 / 2}$
(d) $m$
[1990]
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Solution:
- (c) According to kinetic gas equation $P V=\frac{1}{3} m N u^{2}, u=$ root mean square velocity $\Rightarrow u^{2}=\frac{3 P V}{m N}$ or $u \propto \frac{1}{\sqrt{m}}$ i.e $u \propto m^{-\frac{1}{2}}$
