Six molecules of a gas in a container have speeds $2 \,m/s, 5 \,m/s, 3 \,m/s, 6 \,m/s, 3 \,m/s$ and $5 \,m/s$. The root mean square (r.m.s.) speed is: (in $\,m/s$)

The r.m.s. speed of oxygen molecules at $47^{\circ} C$ is equal to that of the hydrogen molecules kept at . . . . . . ${ }^{\circ} C$. (Mass of oxygen molecule/mass of hydrogen molecule $= 32 / 2$)

At constant temperature,the vapour density of two gases are in the ratio of $6 : 9$. Compare their $v_{rms}$.

The $rms$ speed of $n$ molecules in a gas having speeds $\upsilon_1, \upsilon_2, \upsilon_3, \dots, \upsilon_n$ is equal to:

The root mean square velocity of molecules of a gas is

At what temperature does an oxygen molecule have the same r.m.s. velocity as a hydrogen molecule at $20 \ K$ (in $K$)?