The rate of effusion is directly proportional to the square root of temperature and inversely proportional to the square root of molecular weight.
$ r \propto U ; U =\sqrt{\frac{3 RT }{ M }}$
$ r \propto \sqrt{\frac{ T }{ M }}$
$\therefore \frac{ r _{ N _{2}}}{ r _{ SO _{2}}}=\sqrt{\frac{ T _{ N _{2} M _{ SO _{2}}}}{ T _{ SO _{2} M _{ N _{2}}}}}$
The rate of effusion of $N _{2}$ is $1.625$ times than that of $SO _{2}$ at $50^{\circ} C$. or
$\frac{ r _{ N _{2}}}{ r _{ SO _{2}}}=\sqrt{\frac{ T _{1} \times 64}{(50+273) \times 28}}=1.625$
$T _{2}=373\, K$
At $373\, K$, the rate of effusion of $N _{2}$ would be $1.625$ times than that of $SO _{2}$ at $50^{\circ} C$.