6.4 Nuclear and Particle Physics
6.4.1 The Nuclear Atom
Learners should be able to demonstrate and apply their knowledge and understanding of:
(a) alpha-particle scattering experiment; evidence of a small charged nucleus
(b) simple nuclear model of the atom; protons, neutrons and electrons
(c) relative sizes of atom and nucleus
(d) proton number; nucleon number; isotopes; notation for the representation of nuclei
(e) strong nuclear force; short-range nature of the force; attractive to about 3 fm and repulsive below about 0.5 fm 1 fm = 10–15 m
(f) radius of nuclei; where r 0 is a constant and A is the nucleon number
(g) mean densities of atoms and nuclei.
6.4.2 Fundamental Particles
Learners should be able to demonstrate and apply their knowledge and understanding of:
(a) particles and antiparticles; electron–positron, proton-antiproton, neutron-antineutron and neutrino-antineutrino HSW7, 9
(b) particle and its corresponding antiparticle have same mass; electron and positron have opposite charge; proton and antiproton have opposite charge
(c) classification of hadrons; proton and neutron as examples of hadrons; all hadrons are subject to the strong nuclear force
(d) classification of leptons; electron and neutrino as examples of leptons; all leptons are subject to the weak nuclear force
(e) simple quark model of hadrons in terms of up (u), down (d) and strange (s) quarks and their respective anti-quarks (f) quark model of the proton (uud) and the neutron (udd)
(g) charges of the up (u), down (d), strange (s), anti‑up ( ) u , anti-down ( ) d and the anti-strange ( )s quarks as fractions of the elementary charge e
(h) beta-minus (β- ) decay; beta-plus (β+) decay
You do not need the Feymann diagrams at all (the ones with the arrows and squiggly lines)
(i) β– decay in terms of a quark model
(j) β+ decay in terms of a quark model;
(k) balancing of quark transformation equations in terms of charge
(l) decay of particles in terms of the quark model
6.4.3 Radioactivity
Learners should be able to demonstrate and apply their knowledge and understanding of:
(a) radioactive decay; spontaneous and random nature of decay
(b) (i) α-particles, β-particles and γ-rays; nature, penetration and range of these radiations
(ii) techniques and procedures used to investigate the absorption of α-particles, β-particles and γ-rays by appropriate materials
(c) nuclear decay equations for alpha, beta-minus and beta-plus decays; balancing nuclear transformation equations
(d) activity of a source; decay constant λ of an isotope; A=λN
e) (i) half-life of an isotope; up to here
(ii) techniques and procedures used to determine the half-life of an isotope such as protactinium
(f) (i) the equations where A is the activity and N is the number of
undecayed nuclei
(ii) simulation of radioactive decay using dice
(g) graphical methods and spreadsheet modelling of the equation
(h) radioactive dating, e.g. carbon-dating
6.4.4 Nuclear Fission and Fusion
Learners should be able to demonstrate and apply their knowledge and understanding of:
(a) Einstein’s mass–energy equation;
(b) energy released (or absorbed) in simple nuclear reactions
(c) creation and annihilation of particle–antiparticle pairs
(d) mass defect; binding energy; binding energy per nucleon
(e) binding energy per nucleon against nucleon number curve; energy changes in reactions
(f) binding energy of nuclei using and masses of nuclei
(g) induced nuclear fission; chain reaction
(h) basic structure of a fission reactor; components – fuel rods, control rods and moderator
(i) environmental impact of nuclear waste
(j) nuclear fusion; fusion reactions and temperature
(k) balancing nuclear transformation equations.