Slow neutrons can bring about the fussion of

Options

A. `._(92)U^(235)`
B. `._(82)U^(238)`
C. `._(82)Pb^(207)`
D. `._(88)U^(226)`

Answer

To solve the question "Slow neutrons can bring about the fission of," we need to understand the concepts of nuclear fission and the role of neutrons in this process.

### Step-by-Step Solution:

1. **Understanding Fission**:
- Fission is a nuclear reaction in which a heavy nucleus splits into smaller nuclei, along with the release of energy. This process typically occurs in heavy and unstable nuclei.

2. **Role of Neutrons**:
- Neutrons can initiate fission reactions. Slow (thermal) neutrons are particularly effective in causing fission in certain heavy nuclei. Fast neutrons are required for fission in less unstable nuclei.

3. **Identifying Unstable Nuclei**:
- Among the given options, we need to identify which nuclei are highly unstable and can undergo fission when bombarded with slow neutrons.

4. **Analyzing the Given Nuclei**:
- We are provided with four nuclei. We need to determine which of these is the most unstable and can be induced to fission by slow neutrons.
- The most commonly known nucleus that undergoes fission with slow neutrons is Uranium-235 (U-235), which has an atomic number of 92.

5. **Conclusion**:
- Based on the analysis, the nucleus that can undergo fission with slow neutrons is Uranium-235 (U-235), which is highly unstable and can be split to release energy.

### Final Answer:
The answer is Uranium-235 (U-235).

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