### Correct Option: B. Barium-141 #### Detailed Explanation: Nuclear fission is a process in which a heavy nucleus, such as uranium-235, splits into two or more smaller nuclei, along with the release of a significant amount of energy. This process is fundamental to nuclear reactors and atomic bombs. 1. **Understanding Fission Products**: - When uranium-235 undergoes fission, it absorbs a neutron and becomes unstable. This instability causes the nucleus to split into two smaller nuclei, known as fission products. Along with these smaller nuclei, additional neutrons are released, which can initiate further fission reactions (this is known as a chain reaction). 2. **Common Fission Products**: - The fission of uranium-235 typically produces a variety of fission products, including isotopes of elements like barium, krypton, strontium, and others. Barium-141 is one of the most commonly observed fission products from the fission of uranium-235. 3. **Why Barium-141 is Correct**: - Barium-141 (Ba-141) is a stable isotope that is frequently produced in the fission of uranium-235. The fission reaction can be represented as: \[ \text{U-235} + n \rightarrow \text{Ba-141} + \text{Kr-92} + 3n + \text{Energy} \] - In this reaction, uranium-235 absorbs a neutron and splits into barium-141 and krypton-92, along with the release of additional neutrons and energy. #### Why the Other Options are Incorrect: - **A. Helium-4**: - Helium-4 (He-4) is not a product of nuclear fission. Instead, it is commonly produced in nuclear fusion reactions, such as those occurring in stars. In fission, the products are typically heavier elements or isotopes, not light ones like helium. - **C. Carbon-12**: - Carbon-12 (C-12) is a stable isotope of carbon and is not produced in significant amounts during nuclear fission. Carbon is formed in stellar processes and through other nuclear reactions, but it is not a direct product of uranium-235 fission. - **D. Tritium-3**: - Tritium-3 (T-3) is a radioactive isotope of hydrogen. While it can be produced in nuclear reactions, it is not a common product of uranium-235 fission. Tritium is more often produced in fusion reactions or through neutron capture processes. ### Summary of Key Points: - **Nuclear fission** involves the splitting of heavy nuclei, such as uranium-235, into smaller nuclei. - **Barium-141** is a common fission product resulting from the fission of uranium-235. - Other options like **helium-4**, **carbon-12**, and **tritium-3** do not typically result from the fission of uranium-235. - Understanding the products of fission is crucial for applications in nuclear energy and safety. This detailed breakdown should help clarify why Barium-141 is the correct answer and reinforce your understanding of nuclear fission products.