KCET 2021 Physics Solved Paper

Total internal energy of a gas is given as
U=

n

2

‌fRT
where, n= number of moles
and f= degree of freedom.
Given, ndiatoemic=nmonoatomic=2
As, fmonoatomic=3
fdiatoemic=5
⇒ Umonoatomic=

2

2

×3‌RT=3‌RT
Udiatoemic=

2

2

×5‌RT=5‌RT
∴ Total internal energy of the mixture of gases,
Utotal=Umonoatomic+Udiatomic
=3‌RT+5‌RT=8‌RT