To determine the correct curve for binding energy per nucleon plotted against the mass number for stable nuclei, let's analyze the physical meaning of the graph:
The binding energy per nucleon is known to vary with the mass number. It usually peaks for nuclei with intermediate mass numbers and then decreases for heavier nuclei. This trend is a consequence of the nuclear forces and stability.
For light nuclei, as the mass number increases, the binding energy per nucleon generally increases because more nucleons mean more nuclear forces binding them together effectively.
The curve typically peaks around iron (Fe) with a mass number around 56. This is where the binding energy per nucleon is highest because these are the most stable nuclei, indicating that fusion or fission reactions involving these nuclei will tend to be exothermic.
As the mass number continues to increase for heavier elements, the binding energy per nucleon typically decreases. This is because the repulsive force between the positively charged protons becomes significant, and additional nucleons do not contribute as efficiently to the binding energy.
The correct curve from the image is expected to show:
An initial increase in binding energy per nucleon with mass number for lighter nuclei.
A peak at intermediate mass numbers, signifying the most stable nuclei.
A decrease in binding energy per nucleon for heavy nuclei.
Reviewing the options in the image, curve C correctly represents this pattern.
