UPSEE 2019 Solved Paper

Here, the ratio of specific heat of one mole of monoatomic gas, γ1=

5

3

and one mole of diatomic gas, γ2=

7

5

As we know, CV for a mixture
CVmix =

n1CV1+n2CV2

n1+n2

and CPmix=

n1CP1+n2CP2

n1+n2

Now,
γmix =

CPmix

CVmix

=

n1CP1+n2CP2

n1CV1+n2CV2

........(i)
As, γ=

CP

CV

and CP−CV=R
So, for γ1=

5

3

we get, CP1=

5

2

R and
CV1=

3

2

R
Similarly, for γ2=

7

5

we get, CP2=

7

2

R and CV2=

5

2

R
Hence, from Eq. (i), we get
λmix =

1× 5 2 +1× 7 2

1× 3 2 +1× 5 2

=

5+7

3+5

=

12

8

=1.50
Hence, the ratio of specific heat of mixture is 1.50.