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 $$\Delta U = n C_v (T_f - T_i) = \frac{nR}{\gamma - 1}(T_f - T_i)$$, where $$\gamma = \frac{C_p}{C_v}$$, $$T_i$$ = initial temperature, $$T_f$$ = final temperature.
Statement II: Relation between degree of freedom $$f$$ and $$ \gamma$$ (= $$C_p/C_v$$) is $$\left(\gamma = 1 + \frac{2}{f}\right)$$.
Choose the correct answer from the options given below