Probing Deep Into Matter

What Probing Deep Into Matter covers

Probing Deep Into Matter is examined in all three written papers — the specification states that Components 01, 02 and 03 each assess content from across all the teaching modules, so nothing is confined to one paper. It covers particle accelerators and high-energy beams, scattering and the nuclear atom, paths of scattered particles and closest approach, discrete energy levels in atoms, electron standing waves and the confined electron, quarks, hadrons and leptons, conservation laws and nuclear equations, charged particles in detectors and magnetic fields and relativistic energy and the relativistic factor.

The 9 subtopics

Each one has its own page.

• Particle accelerators and high-energy beamsRecall questions on why probing small structures needs high energy, how a linear accelerator works and why its voltage alternates, magnets and vacuum in a ring, and creating new particles.Open →
• Scattering and the nuclear atomRecall questions on the alpha-particle scattering arrangement, what most particles and a few particles did and what each shows, why a vacuum, a thin foil and gold were used, the sizes of atoms and nuclei and their volume ratio, the model it overturned, the negligible effect of electrons, high-energy electron scattering, and the nuclear atom as a model.Open →
• Paths of scattered particles and closest approachRecall questions on paths near and straight at a nucleus, the energy exchange on approach, calculating a closest approach, why it only bounds the nuclear radius, and how scattering varies with angle.Open →
• Discrete energy levels in atomsRecall questions on energy levels and the evidence of line spectra, ΔE = hf, frequency and wavelength calculations for a transition, absorption against emission spectra, electron collisions as evidence, electrons below the excitation energy, ionisation energy, negative energy values, ground and excited states, excitation against ionisation, and exciting an atom with a 10.4 V electron.Open →
• Electron standing waves and the confined electronRecall questions on why confinement gives discrete energies, the allowed wavelengths and resulting momentum and energy, nodes in higher states, why an atom has a definite size, and the model's limits.Open →
• Quarks, hadrons and leptonsRecall questions on the quark compositions and charges of protons, neutrons and antiprotons, the charges of up and down quarks, hadrons, leptons and gluons, antiparticles and the positron, lepton numbers, neutrinos and why they are hard to detect, why free quarks are never seen, and beta-minus decay at quark level.Open →
• Conservation laws and nuclear equationsRecall questions on the quantities that must balance, how alpha, beta and gamma emission change a nucleus, decay equations, annihilation and pair production, and why a further particle was proposed.Open →
• Charged particles in detectors and magnetic fieldsRecall questions on why tracks curve and what the curvature direction reveals, momentum from a track radius, tracks that spiral or appear from nowhere, invisible neutral particles, and charge-to-mass ratios.Open →
• Relativistic energy and the relativistic factorRecall questions on rest energy from rest mass, electron and proton values in MeV, evaluating the factor at high speeds, total and kinetic energy, and why no massive particle reaches light speed.Open →

What you need to know

Answer each one before you reveal it.

Take Probing Deep Into Matter further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Hadron vs Lepton

  Hadron: a particle built from quarks and feeling the strong interaction, the proton and the neutron being the familiar examples. Lepton: a fundamental particle that is not made of quarks and takes no part in the strong interaction, such as the electron or the neutrino.

• Excitation vs Ionisation

  Excitation: lifting an electron to a higher level while it stays bound to the atom. Ionisation: giving an electron enough energy to escape the atom altogether, leaving the atom positively charged.

• Rest energy vs Total energy

  Rest energy: mc², what a particle has by virtue of its mass alone and the same whatever it is doing. Total energy: γmc², which already includes the kinetic contribution and grows without limit as the speed approaches c.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Why must particles be given very high energies in order to probe small structures?

   Model answer

   The de Broglie wavelength of a particle is h/p, so only a large momentum gives a wavelength small enough to resolve detail on the scale of a nucleus or smaller.

2. 2

   Calculate the de Broglie wavelength of a particle whose momentum is 1.0 × 10⁻²¹ N s.

   Model answer

   λ = h/p = 6.63 × 10⁻³⁴ ÷ 1.0 × 10⁻²¹ = 6.6 × 10⁻¹³ m.

3. 3

   Describe how a linear accelerator increases the energy of a charged particle.

   Model answer

   The particle passes through a line of hollow electrodes and is accelerated across each gap by a potential difference, gaining energy qV at every gap so that its energy builds up along the line.

4. 4

   Why must the accelerating voltage in a linear accelerator alternate?

   Model answer

   The particle must always meet a field pointing the right way to speed it up, so the voltage on the electrodes has to reverse in step with the particle's arrival at each gap.

5. 5

   What is the role of magnetic fields in a ring accelerator?

   Model answer

   Magnetic fields provide the centripetal force through F = qvB that bends the beam round the ring, and further magnets focus the beam so it stays narrow.

6. 6

   Calculate the energy in joules gained by a proton accelerated through a potential difference of 2.0 × 10⁶ V.

   Model answer

   The energy gained is qV = 1.60 × 10⁻¹⁹ × 2.0 × 10⁶ = 3.2 × 10⁻¹³ J, which is 2.0 MeV.

What is inside Levo

Six ways to work the same material.

Probing Deep Into Matter revision questions

What does Probing Deep Into Matter cover in OCR A-Level Physics B?

9 subtopics: particle accelerators and high-energy beams, scattering and the nuclear atom, paths of scattered particles and closest approach, discrete energy levels in atoms, electron standing waves and the confined electron, quarks, hadrons and leptons, conservation laws and nuclear equations, charged particles in detectors and magnetic fields and relativistic energy and the relativistic factor. Each one has its own page with questions and model answers.

How is Probing Deep Into Matter organised?

By the OCR H557 specification, subtopic by subtopic, so it matches the order you are taught it in.