Question

The density of air at pressure of ${10}^{5}N{m}^{-2}$ is $1.2kg{m}^{-3}$. Under these conditions the root mean square velocity of the air molecules is $m{s}^{-1}$ is

• A. $500$
• B. $1000$
• C. $1500$
• D. $3000$

Answer 1

Answer: (A)

$500$

$C=\sqrt{\frac{3P}{\rho }}$ (standard result)
$=\sqrt{\frac{3\times {10}^5}{1.2}}$
$=500m{s}^{-1}$