Q.

At what temperature the r.m.s. velocity of a hydrogen molecule equal to that of an oxygen molecule at 47°C                    [2024]

1 80 K  
2 – 73 K  
3 4 K  
4 20 K  

Ans.

(4) 

        Vrms=3RTM(Vrms)H2=(Vrms)O2

         T1M1=T2M2

          T1=M1M2T2=232(273+47)

          =232×320=20K