[UPSC CSE 2026] Nuclear Physics (Q5, 10M)

What do you understand by the packing fraction ' $f$ ' and the binding energy ' $E_b$ ' of a nucleus? Draw the graphs for packing fraction $f$ versus mass number ( $A$ ) and binding energy fraction $f_b \left(= \dfrac{E_b}{A}\right)$ versus mass number ( $A$ ). Further, explain how the graphs of the variation of $f$ and $f_b$ with $A$ have complementary approaches.