# Describe what happens to a large nucleus during nuclear fission and explain how the energy released in this process originates.

> Eduqas GCSE Physics — 9.4 Nuclear fission and fusion · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. A large/heavy nucleus absorbs a neutron (and becomes unstable)
2. The nucleus splits into two smaller/daughter nuclei (and releases neutrons)
3. The total mass of the products is less than the mass of the original nucleus (mass defect / mass is lost)
4. The lost mass is converted into energy (reference to Einstein's mass–energy equivalence or E = mc²)

## Key terms

- [nuclear fission](https://www.gradenine.co.uk/glossary/nuclear-fission)

## Related

- [Revision notes for Eduqas GCSE Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-what-happens-to-a-large-d772f332) · Published by Druglandscape Ltd.