Three closed vessels A, B and C are at the same temperature T and contain gases which obey the Maxwellian distribution of velocities. Vessel A contains only \[{{O}_{2}},B\] only\[{{N}_{2}},\] and \[{{O}_{2}}\] mixture of equal quantities of \[{{O}_{2}}\] and \[{{N}_{2}}\]. If the average speed of the \[{{O}_{2}}\]molecules in vessel A is \[{{V}_{1}}\] that of the \[{{N}_{2}}\] molecules in vessel B is \[{{V}_{2}}\] then the average speed of the \[{{O}_{2}}\] molecules in vessel C is (where M is the mass of an oxygen molecule)

• A. \[({{V}_{1}}+{{V}_{2}})/2\]
• B. \[{{V}_{1}}\]
• C. \[{{({{V}_{1}}{{V}_{2}})}^{1/2}}\]
• D. \[\sqrt{3kT/M}\]