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Ch 42: Nuclear Physics
Knight Calc - Physics for Scientists and Engineers 5th Edition
Knight Calc5th EditionPhysics for Scientists and EngineersISBN: 9780137344796Not the one you use?Change textbook
Chapter 42, Problem 44

Use the graph of binding energy to estimate the total energy released if three ⁴He nuclei fuse together to form a ¹²C nucleus.

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1
Identify the binding energy per nucleon for ⁴He and ¹²C from the graph of binding energy. Binding energy per nucleon is typically given in MeV (Mega-electron Volts).
Calculate the total binding energy for three ⁴He nuclei. Since each ⁴He nucleus has 4 nucleons, the total number of nucleons in three ⁴He nuclei is 12. Multiply the binding energy per nucleon of ⁴He by the total number of nucleons (12).
Determine the total binding energy of the ¹²C nucleus. Multiply the binding energy per nucleon of ¹²C by the total number of nucleons in ¹²C (which is 12).
Find the energy released during the fusion process. Subtract the total binding energy of the three ⁴He nuclei from the total binding energy of the ¹²C nucleus. The difference represents the energy released.
Express the energy released in appropriate units (e.g., MeV) and ensure the result is consistent with the conservation of energy principle.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Binding Energy

Binding energy is the energy required to disassemble a nucleus into its constituent protons and neutrons. It is a measure of the stability of a nucleus; the higher the binding energy, the more stable the nucleus. In fusion reactions, the difference in binding energy before and after the reaction indicates the energy released during the process.
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Nuclear Fusion

Nuclear fusion is the process where two light atomic nuclei combine to form a heavier nucleus, releasing energy in the process. This occurs under conditions of high temperature and pressure, such as in stars. In the case of helium nuclei fusing to form carbon, the energy released is a result of the increased binding energy of the resulting nucleus compared to the original nuclei.
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Energy Release Calculation

To estimate the total energy released in a fusion reaction, one must calculate the difference in binding energy between the reactants and the products. This involves using the binding energy values from a graph or table for the involved nuclei. The energy released can be expressed in MeV (mega-electronvolts) and is a crucial aspect of understanding the efficiency and feasibility of fusion as an energy source.
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