Question

Fission of nuclei is possible because the binding energy per nucleon in them

• A. increases with mass number at high mass numbers
• B. decreases with mass number at high mass numbers
• C. increases with mass number at low mass numbers
• D. decreases with mass number at low mm numbers

Answer 1

Answer: (B)

decreases with mass number at high mass numbers

Answer 2

The binding energy per nucleon for the middle nuclides (from $A=20$ to $A=56$ ) is maximum. Hence, these are more stable.
As the mass number increases, the binding energy per nucleon gradually decreases and ultimately binding energy per nucleon of heavy nuclides (such as uranium etc.) is comparatively low. Hence, these nuclides are relatively unstable. So, they can be fissioned easily.