At what temperature is the root$-$mean$-$square speed of nitrogen molecules equal to the root$-$mean$-$square speed of hydrogen molecules at $9$ oC$?($Hint: The molar mass of hydrogen atoms is $1\mathrm{.}008$ g$/$mol and of nitrogen atoms is $14\mathrm{.}007$ g$/$mol$.$ The molar mass of H$2$ is twice the molar mass of hydrogen atoms, and similarly for N$2.)$ The answer is in degree C$.$