Q.

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Statement I: Change in internal energy of a system containing n mole of ideal gas can be written as

ΔU=nCv(Tf-Ti)=nRγ-1(Tf-Ti), where γ=CpCv,  Ti=initial temperature,  Tf=final temperature.

Statement II: Relation between degree of freedom f and γ(=CpCv) is (γ=1+2f).             

Choose the correct answer from the options given below                    [2026]

1 Both A and R are true and R is the correct explanation of A  
2 Both A and R are true but R is NOT the correct explanation of A  
3 A is true but R is false  
4 A is false but R is true  

Ans.

(2)

ΔU=nCv(Tf-Ti)=nRγ-1(Tf-Ti)

γ=CpCv=(f2+1)Rf2R=1+2f