Question

Which of the following figures correctly represent the shape of the curve of binding energy per nucleon as a function of mass number?

• A.
• B.
• C.
• D.

Hint:

The binding energy per nucleon increases for lighter elements and decreases for heavier elements. The curve reaches a maximum near iron.

Answer 1

The Correct Option is B

The binding energy per nucleon is a measure of the stability of a nucleus, and it generally varies with the mass number in a specific way. As the mass number increases, the shape of the curve can be described as follows:

• For light nuclei (mass numbers less than 20), the binding energy per nucleon increases sharply.
• In the region of medium mass numbers, around the element iron, the curve reaches a maximum; this indicates that these nuclei are the most stable.
• For heavier nuclei beyond this point, the binding energy per nucleon gradually decreases because of increased repulsive forces among protons.

These characteristics form a curve that starts at a lower value for very light nuclei, rises to a peak at medium mass numbers, and then falls off gradually for heavier elements. Given these points, the correct option that matches the description of the binding energy per nucleon as a function of mass number is: