The average energy of molecules in a sample of oxygen gas at 300K are `6.2 J xx 10^(-21)` J. The corresponding values at 600K are

Options

A. `8 cdot 78xx10^(-21) J, 684 ms^(-1)`
B. `6 cdot 21 xx10^(-21)J, 968 ms^(-1)`
C. `12 cdot 42 xx10^(-21) J, 968 ms^(-1)`
D. `12 cdot 42 xx10^(-21) J, 968 ms^(-1)`

Answer

C

Explanation

`K.E. prop` temperature
`therefore (E_(2))/(E_(1))=(T_(2))/(T_(1)) rArr E_(2)=2E_(1)=12 cdot 42 xx10^(-21) J`
And `v_(rms) prop sqrt(T)`
`(v_(2))/(v_(1))=sqrt((T_(2))/(T_(1)))`
`rArr v_(2)=v_(1) sqrt((600)/(300)) =1 cdot 414 xx 484 =684 ms^(-1)`
Thus, correct choice is (c).