Q: Binding energy per nucleon versus mass number curve for nuclei is shown in the fig. W, X, Y and Z are four nuclei indicated on the curve. The process that would release energy is
(a) Y → 2Z
(b) W → X + Z
(c) W → 2Y
(d) X → Y + Z
Ans: (c)
Sol: Energy is released , When total B.E. of products > Reactants
Y → 2Z ⇒ 2 × 5 × 30-8.5 × 60= -210 Me V
W → X + Z ⇒ 8 ×90+5 × 30-7.5 ×120=-30 Me V
W → 2Y ⇒ 2 ×8.5 × 60-7.5 ×120=120 Me V
X → Y + Z ⇒ 8.5 ×60+5 ×30-8 ×90=-60 Me V