BThe velocity of atomic oxygen doubles
b
$V _{ mms }=\sqrt{\frac{3 RT }{ M }}$
$T \rightarrow 2 T$
$M \rightarrow \frac{ M }{2}$
$V _{ rms } \propto \sqrt{\frac{ T }{ M }}$
$\Rightarrow\left(V_{\text {rms }}\right)_{\text {atomic }}=\left(V_{\text {rms }}\right)_{\text {molecular }} \times \sqrt{\frac{2}{1 / 2}}=2\left(V_{\text {ms }}\right)_{\text {molecular }}$