Particles and Radiation

Across

3. A force that acts between nucleons in a nucleus to keep it stable. It is attractive at distances of up to 3fm and repulsive at separations less than 0.5fm.
6. The number of protons present in the nucleus of a given element.
8. A quantum number that is conserved in strong interactions but not in weak interactions. This reflects that strange particles are always produced in pairs.
10. A group of elementary subatomic particles, consisting of electrons, muons and neutrinos.
12. The minimum energy required to remove an electron from a metal’s surface.
15. The process of a particle and its antiparticle colliding and being converted into energy. The energy is released in two photons to conserve momentum.
16. The process of a sufficiently high-energy photon converting into a particle and its corresponding antiparticle. To conserve momentum, this usually occurs near a nucleus.
17. The process of an unstable nucleus emitting an alpha particle (two protons and two neutrons) to become more stable.
18. A packet of energy.
19. The exchange particles that transmit the four fundamental interactions between particles.
21. The process of a neutron inside a nucleus turning into a proton, and emitting a beta-minus particle (an electron) and a antineutrino.
22. The sum of the number of protons and neutrons in a given nucleus.
24. All particles have a corresponding antiparticle with the same mass but opposite charge and conservation numbers.
25. A subatomic particle whose existence was hypothesised to maintain the conservation of energy in beta decay.
27. A class of hadron, that is made up of three quarks. The proton is the only stable baryon.
28. A proton or neutron.
29. The minimum potential difference required to stop the highest kinetic energy electrons from leaving the metal plate in the photoelectric effect.
30. A class of subatomic particle that experiences the strong nuclear interaction.
31. The process of a proton inside a nucleus turning into a neutron, and emitting a beta-plus particle (a positron) and a neutrino.
33. Particles that are produced through the strong interaction but decay through the weak interaction.
34. The work done to accelerate an electron through a potential difference of 1V. 1eV is equal to the charge of an electron (E=qv).

Down

1. The process of an electron taking in exactly the right quantity of energy to move to a higher energy level.
2. Data from isotopes that can be used for a purpose, such as carbon dating.
4. The most stable energy level that an electron can exist in.
5. A type of meson and the exchange particle for the strong nuclear force.
7. The process of an atom losing an orbital electron and becoming charged.
9. A type of meson that decays into pions.
11. The minimum frequency of photons required for photoelectrons to be emitted from the surface of a metal plate through the photoelectric effect. It is equal to the metal’s work function divided by Planck’s constant.
13. A quantum number that is conserved in all particle interactions. Both electron lepton numbers and muon lepton numbers must be conserved.
14. A quantum number that is conserved in all particle interactions. Baryons have a baryon number of +1 and non-baryons have a baryon number of 0.
18. A positively charged particle that is the antiparticle of an electron.
20. Defined and distinct energies at which electrons can exist in an atom. An electron cannot exist between energy levels.
23. Same number of protons but different numbers of neutrons.
26. The spreading of electrons as they pass through a gap similar to the magnitude of their de Broglie wavelength. It is evidence of the wave-like properties of particles.
32. A class of hadron that is made up of a quark and antiquark pair. Muon A type of lepton that decays into electrons.