🔋college physics i – introduction review

key term - Uranium-235

Definition

Uranium-235 is a fissile isotope of the element uranium that is the primary fuel used in nuclear reactors and nuclear weapons. It is the only naturally occurring isotope that is fissile, meaning it can sustain a nuclear chain reaction. This unique property of uranium-235 makes it central to the topics of half-life, binding energy, nuclear fission, and nuclear weapons.

5 Must Know Facts For Your Next Test

  1. Uranium-235 has a half-life of 704 million years, meaning it takes 704 million years for half of a given amount of uranium-235 to decay.
  2. The binding energy of uranium-235 is approximately 7.6 MeV per nucleon, which is relatively high compared to other stable nuclei, making it a favorable target for nuclear fission.
  3. The fission of uranium-235 is the primary process used in nuclear power plants to generate electricity, as well as in nuclear weapons to create a devastating explosive force.
  4. The enrichment of uranium-235 is a critical step in the production of nuclear fuel for power plants and the development of nuclear weapons.
  5. The controlled fission of uranium-235 in nuclear reactors can be used to produce heat, which is then used to generate steam and drive turbines to produce electricity.

Review Questions

  • Explain how the half-life of uranium-235 is related to its radioactive decay and the concept of activity.
    • The half-life of uranium-235 is the time it takes for half of a given amount of the isotope to decay. As uranium-235 undergoes radioactive decay, its activity, or the rate of radioactive disintegrations, decreases exponentially over time. The half-life of 704 million years means that after this time, only half of the original amount of uranium-235 will remain, and the activity will have decreased by half. This relationship between half-life and activity is a fundamental principle in understanding the behavior of radioactive materials like uranium-235.
  • Describe the role of the binding energy of uranium-235 in the process of nuclear fission.
    • The binding energy of a nucleus is the energy required to separate the protons and neutrons that make up the nucleus. The relatively high binding energy of uranium-235, at 7.6 MeV per nucleon, makes it a favorable target for nuclear fission. When the uranium-235 nucleus is split, the total binding energy of the resulting lighter nuclei is less than the original uranium-235 nucleus. This difference in binding energy is released in the form of kinetic energy of the fission products and the neutrons emitted, as well as in the form of heat. This release of energy is the driving force behind the fission process and the basis for the use of uranium-235 in nuclear power plants and nuclear weapons.
  • Evaluate the significance of the fissile nature of uranium-235 in the context of nuclear weapons development and the potential risks associated with its proliferation.
    • The fact that uranium-235 is the only naturally occurring fissile isotope, meaning it can sustain a nuclear chain reaction, is central to its use in nuclear weapons. The ability to enrich uranium-235 to higher concentrations allows for the development of nuclear weapons with devastating explosive power. The proliferation of uranium-235 and the technology to enrich it has been a major concern in the international community, as it increases the risk of nuclear weapons falling into the hands of rogue states or terrorist groups. The potential for uranium-235 to be used in nuclear weapons, coupled with the challenges of securing and safeguarding this material, highlights the importance of strict regulations and international cooperation to prevent its misuse and the catastrophic consequences that could result.