Nuclear Binding Energy and Nuclear Reactions

This page delves into the concepts of nuclear binding energy, mass defect, and nuclear reactions such as fission and fusion.

Nuclear binding energy is the energy required to separate a nucleus into its constituent nucleons. It is closely related to the concept of mass defect, which is the difference between the mass of a nucleus and the sum of its individual nucleon masses.

Definition: The binding energy of nucleus is the energy required to separate a nucleus into its constituent nucleons.

Vocabulary: Mass defect refers to the difference between the mass of a nucleus and the sum of its individual nucleon masses.

The page explains that mass and energy are interchangeable at the nuclear level, following Einstein's famous equation E = mc². It introduces the atomic mass unit (u) as a convenient measure for atomic masses, with 1u equivalent to 931.5 MeV of energy.

Example: A change in 1u of mass is equivalent to 931.5 MeV of energy released.

The concept of binding energy per nucleon is introduced, which is crucial for understanding nuclear stability and the potential for nuclear reactions.

Definition: Binding energy per nucleon is the binding energy of a nucleus divided by the number of nucleons in the nucleus.

The page then discusses nuclear fission and fusion:

Nuclear Fission:

• Splitting of a large nucleus into two daughter nuclei
• Occurs in large, unstable nuclei or can be induced
• Releases energy because the smaller daughter nuclei have a higher binding energy per nucleon

Nuclear Fusion:

• Joining of two small nuclei to form one larger nucleus
• Occurs in small nuclei
• Releases more energy than fission but requires extremely high temperatures

Highlight: Nuclear fusion vs fission energy output: Fusion releases more energy than fission, but it can only happen at extremely high temperatures (in stars).

The page concludes with a graph of binding energy per nucleon against nucleon number, which helps identify whether an element can undergo fusion or fission.

Example: Elements smaller than iron can undergo fusion, while elements larger than iron can undergo fission.