9702 · 11.2
Fundamental particles flashcards
Revision flashcards for Cambridge 9702 Fundamental particles (syllabus 11.2). Flip, recall, then mark a real past-paper question.
Card
What did Rutherford's scattering experiment reveal about the structure of an atom?
It revealed that an atom consists mostly of empty space with a tiny, dense, positively charged nucleus.
Card
How are baryons and mesons distinguished based on their quark composition?
Baryons are composed of three quarks (e.g., protons, neutrons), while mesons are composed of one quark and one antiquark (e.g., pions).
Card
What quark flavour change occurs during beta-minus decay, and how does it affect the proton number?
A down quark changes into an up quark (d → u), resulting in an increase of the proton number by 1.
Card
What is meant by the "specific charge" of a particle?
It is the ratio of the particle's charge to its mass (Charge / Mass), measured in coulombs per kilogram (C/kg).
Card
Why do beta particles exhibit a continuous energy spectrum, unlike alpha particles which have discrete energies?
Beta particles share the decay energy with an accompanying (anti)neutrino, leading to a continuous distribution of kinetic energies for the beta particle.
Card
What are isotopes?
Atoms of the same element (same proton number Z) but with different numbers of neutrons.
Card
List the six 'flavours' of quarks.
Up, down, charm, strange, top, and bottom.
Card
How does an antiparticle differ from its corresponding particle?
An antiparticle has the same mass but opposite charge and other quantum numbers (like lepton number).
Card
What is an alpha particle composed of?
Two protons and two neutrons, identical to a helium nucleus.
Card
Which fundamental force is responsible for beta decay?
The weak interaction.
Card
What are the two main classes of fundamental matter particles in the Standard Model?
Quarks and Leptons.
Card
What happens during particle-antiparticle annihilation?
The particle and antiparticle collide, converting their total mass into energy, typically in the form of two or more high-energy photons (gamma rays).
Card
What is pair production?
The creation of a particle-antiparticle pair from a high-energy photon passing near a nucleus. The photon's energy must be at least the sum of the rest masses of the created pair.
Card
What is the quark composition of a positive pion (π⁺)?
A positive pion is a meson composed of an up quark and a down antiquark (uđ).