Nuclear Physics

6. A hadron made of a quark and an antiquark (e.g., Pions, Kaons).
8. The rate of decay of a sample (number of nuclei decaying per second). Unit: Becquerel.
9. Material (e.g., water, graphite) in a reactor that slows down fast neutrons to thermal speeds, making them more likely to cause fission.
10. A helium nucleus. Highly ionising but low penetration (stopped by paper/skin).
12. Nuclei of the same element) with a different number of neutrons.
15. A particle that cannot be split into smaller, simpler components (e.g., quarks, leptons).
17. The splitting of a large, unstable nucleus into two smaller, more stable daughter nuclei, releasing energy and neutrons.
19. The energy required to separate a nucleus into its constituent protons and neutrons.
20. Particles composed of quarks that experience the strong nuclear force (e.g., protons, neutrons, pions, kaons).
21. Responsible for beta decay; acts over a very short range.

1. Repulsive force between protons, which the strong force must overcome.
2. Fundamental particles that do not experience the strong nuclear force (e.g., electrons, neutrinos).
3. Neutrons released in fission go on to cause further fission reactions.
4. Fast-moving electrons or positrons emitted from the nucleus. Moderately ionising, stopped by a few millimetres of aluminium.
5. Fundamental components of hadrons.
7. A proton or a neutron found in the nucleus.
11. The difference between the mass of a nucleus and the sum of the masses of its individual nucleons.
13. A hadron made of three quarks (e.g., protons, neutrons).
14. The joining of two smaller nuclei to form a larger, more stable nucleus, releasing energy (happens at high temperatures/pressures).
16. Particles with the same mass as their counterparts but opposite charge (e.g., Positron is the antiparticle of an electron).
18. The force that holds nucleons together.fm. It is attractive up to 3fm and repulsive below 0.5.