Nuclear and Particle Physics | OCR A-Level Physics A (H556)

Nuclear and Particle Physics

179 questions
16 subtopics
Module 6: Particles and medical physics
Paper 2 and Paper 3

Inside the atom: the evidence for the nucleus, quarks and leptons, radioactive decay and its mathematics, and the energy released by fission and fusion..

It covers alpha-particle scattering and the nuclear model, proton number, nucleon number and isotopes, the strong nuclear force and nuclear radius, particles, antiparticles and hadrons, leptons and the quark model, quark composition and charges, beta decay in the quark model, radioactive decay and the three radiations, nuclear decay equations, activity, decay constant and half-life, exponential decay and radioactive dating, mass-energy equivalence, annihilation, mass defect and binding energy, binding energy per nucleon and induced fission, the fission reactor and nuclear waste and nuclear fusion and balancing nuclear equations.

Sample questions from Nuclear and Particle Physics

Answer each one closed book first, then open the answer.

Alpha-particle scattering and the nuclear model

What evidence does large-angle scattering of alpha particles provide about atomic structure?

Show the answer
It provides evidence that the positive charge and most of the mass of an atom is concentrated in a small central nucleus.
The strong nuclear force and nuclear radius

At what nucleon separation does the strong nuclear force become repulsive, and why is this significant?

Show the answer
The strong nuclear force becomes repulsive at separations below about 0.5 fm, preventing nucleons from overlapping.
Leptons and the quark model

Why are electrons classified as leptons rather than hadrons?

Show the answer
Electrons experience the weak nuclear force but do not experience the strong nuclear force, which is the defining characteristic of leptons.
Beta decay in the quark model

What quantity must balance on both sides of a quark transformation equation?

Show the answer
Electric charge.
Nuclear decay equations

In alpha decay, how do the nucleon number and proton number of the parent nucleus change?

Show the answer
The nucleon number decreases by 4 and the proton number decreases by 2.
Exponential decay and radioactive dating

State the exponential decay equation for the number of undecayed nuclei N at time t.

Show the answer
N = N₀e^(−λt)
Annihilation, mass defect and binding energy

Why must the minimum photon energy for pair creation equal 2m₀c² rather than just m₀c²?

Show the answer
Because pair creation produces both a particle and its antiparticle, each with rest mass m₀, so the total rest mass energy required is twice that of a single particle.
The fission reactor and nuclear waste

What materials are typically used to make control rods, and why?

Show the answer
Boron or cadmium, because they have high neutron absorption cross-sections.

The 16 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Alpha-particle scattering and the nuclear model	Recall questions on the alpha-particle scattering experiment and what it showed, the simple nuclear model, and the orders of magnitude of atomic and nuclear radii.	9
Proton number, nucleon number and isotopes	Recall questions on proton number and nucleon number, the femtometre, protons, neutrons and electrons with their charges, isotopes and nuclear notation.	8
The strong nuclear force and nuclear radius	Recall questions on the range and behaviour of the strong force, R = r₀A^(1/3), and the density of nuclear matter.	9
Particles, antiparticles and hadrons	Recall questions on particles and antiparticles, the positron, antiproton and antineutron, and classifying protons, neutrons and electrons as hadrons or leptons.	8
Leptons and the quark model	Recall questions on the electron and neutrino as leptons, and on the simple quark model of hadrons.	8
Quark composition and charges	Recall questions on the charges of up, down and strange quarks and antiquarks, and the quark composition and overall charge of protons and neutrons.	9
Beta decay in the quark model	Recall questions on the particles emitted in beta-minus and beta-plus decay, the nucleon and quark changes involved, and balancing quark transformation equations.	10
Radioactive decay and the three radiations	Recall questions on the spontaneous and random nature of decay, the composition, range, ionising power and absorbers of alpha, beta and gamma radiation, and the radiation absorption experiment.	21
Nuclear decay equations	Recall questions on how nucleon and proton numbers change in alpha, beta-minus and beta-plus decay, the general alpha decay equation, and the quantities conserved when balancing nuclear equations.	8
Activity, decay constant and half-life	Recall questions on activity and A = λN, the decay constant, half-life and its calculation, the protactinium experiment to find half-life, and the straight-line graph used to find the decay constant.	16
Exponential decay and radioactive dating	Recall questions on the exponential decay equations for activity and undecayed nuclei, modelling decay with dice and spreadsheets, and carbon dating and how the age of a sample is calculated.	19
Mass-energy equivalence	Recall questions on E = mc², energy released from the mass difference in a nuclear reaction, and the steps of calculating that energy.	8
Annihilation, mass defect and binding energy	Recall questions on annihilation and pair creation, the minimum photon energy for pair creation, mass defect, binding energy and the steps of calculating binding energy.	15
Binding energy per nucleon and induced fission	Recall questions on binding energy per nucleon and its calculation, the binding energy curve and iron-56, why fusion and fission release energy, induced fission, chain reactions and slowing neutrons.	13
The fission reactor and nuclear waste	Recall questions on fuel rods, control rods, moderators, nuclear waste and its environmental risks, and the decisions involved in building nuclear power stations.	10
Nuclear fusion and balancing nuclear equations	Recall questions on nuclear fusion and the temperatures and plasma it requires, and conserving nucleon and proton numbers, electron values and neutrinos when balancing nuclear equations.	8

Nuclear and Particle Physics is 179 of the 1,862 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.