Nuclear fission is triggered when the critical energy threshold, compared to the neutron binding energy of the target atoms, is_________________?
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Answer: B. more
Explanation
Nuclear fission occurs because the incoming neutron supplies excitation energy to the target nucleus. This added excitation energy must surpass the critical activation threshold to split the atom. When the available energy is higher than this threshold, the nucleus undergoes rapid fission. The neutron binding energy represents the energy released when a single neutron joins a nucleus. Critical energy is the activation energy barrier required to deform a heavy nucleus into fission fragments. Quantum mechanics and nuclear shell models dictate these precise energy thresholds for different isotopes.
Understanding this energy balance is crucial for designing safe nuclear power plant reactors. Engineers use these thresholds to determine which uranium or plutonium isotopes sustain chain reactions. Controlling this energy surplus prevents runaway reactions or unexpected core meltdowns during operation. Option A is incorrect because equal energy leaves the nucleus stable without causing fission. Option C is wrong because lower energy fails to overcome the vital nuclear binding forces. Option D and E are incorrect because a strict threshold criterion always governs fission.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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