Question

Two nuclei with lower binding energy per nucleon form a nucleus with more binding energy per nucleon. (i) What type of nuclear reaction is it?

Hint:

Fusion reactions occur when two lighter nuclei combine to form a heavier nucleus, releasing energy in the process.

Answer 1

When two nuclei with lower binding energy per nucleon combine to form a nucleus with a higher binding energy per nucleon, the process is called nuclear fusion. 

1. Explanation of Nuclear Fusion:

In nuclear fusion, two light atomic nuclei (such as hydrogen isotopes, like deuterium and tritium) combine to form a heavier nucleus (such as helium). The key feature of this process is that the resulting nucleus has a higher binding energy per nucleon compared to the original nuclei, meaning the nucleus is more stable after fusion.

• The binding energy per nucleon is a measure of how tightly the nucleons (protons and neutrons) are bound within the nucleus. The greater the binding energy per nucleon, the more stable the nucleus.
• In the case of fusion, the binding energy per nucleon increases because the resulting nucleus is closer to the "optimal" binding energy, which is typically around iron-56 (which has the highest binding energy per nucleon).
• This release of energy during fusion is responsible for the tremendous energy output observed in stars, including the Sun, and is the principle behind hydrogen bombs and fusion reactors.

2. Why Fusion Happens with Lower Binding Energy Nuclei:

For elements lighter than iron (which have relatively lower binding energies per nucleon), fusion occurs because the resulting nucleus, which is heavier than the original nuclei, will have a higher binding energy per nucleon. This means that energy is released during the fusion process, making it energetically favorable.

3. Conclusion:

The type of nuclear reaction where two nuclei with lower binding energy per nucleon form a nucleus with more binding energy per nucleon is nuclear fusion.