Twenty flashcards covering nuclear structure and decay, and the fundamentals of particle physics. Includes isotopes, alpha/beta/gamma decay, half-life calculations, binding energy per nucleon, nuclear fission and fusion, and the quarks, leptons and force carri...
Twenty flashcards covering nuclear structure and decay, and the fundamentals of particle physics. Includes isotopes, alpha/beta/gamma decay, half-life calculations, binding energy per nucleon, nuclear fission and fusion, and the quarks, leptons and force carriers of the Standard Model. Suited to A-Level and AP Physics 2 revision.
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The mass number (A) is the total number of protons plus neutrons. The atomic number (Z) is the number of protons, which determines the element.
An atom of the same element (same Z) with a different number of neutrons, and therefore a different mass number A.
Emission of a helium nucleus (2 protons, 2 neutrons), reducing mass number by 4 and atomic number by 2. Alpha particles are the least penetrating, stopped by paper or skin.
A neutron converts to a proton, emitting an electron and an antineutrino. Atomic number increases by 1; mass number is unchanged. Beta particles are stopped by a few mm of aluminium.
Emission of high-energy electromagnetic radiation from an excited nucleus, with no change in mass or atomic number. Gamma rays are the most penetrating, requiring thick lead or concrete to stop.
The time taken for half of the radioactive nuclei in a sample, on average, to decay ā a constant for a given isotope regardless of sample size.
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.
Low-level ionising radiation always present in the environment, from sources including radon gas, cosmic rays, rocks/soil and medical procedures.
The energy required to separate a nucleus into its individual protons and neutrons, released when the nucleus forms ā a measure of nuclear stability.
Iron-56 is among the most stable nuclei. Fusing lighter elements or fissioning heavier ones both release energy by moving toward this peak.
The splitting of a heavy nucleus (e.g. uranium-235) into two lighter nuclei, releasing energy and typically additional neutrons that can sustain a chain reaction.
The combination of two light nuclei (e.g. isotopes of hydrogen) into a heavier nucleus, releasing large amounts of energy ā the process powering stars.
Nuclei are positively charged and repel each other electrostatically; enormous kinetic energy (high temperature) is needed to overcome this Coulomb barrier and allow the strong force to bind them.
The minimum mass of fissile material needed to sustain a self-supporting chain reaction, where each fission triggers on average one further fission.
Made of neutron-absorbing material (e.g. boron, cadmium), they are inserted or withdrawn to regulate the reaction rate and keep it at a stable, controlled level.
Up, down, charm, strange, top, bottom ā the fundamental constituent particles of protons, neutrons and other hadrons.
A proton is two up quarks and one down quark (uud). A neutron is one up quark and two down quarks (udd).
Gravity (graviton, theoretical), electromagnetism (photon), strong nuclear force (gluon), weak nuclear force (W and Z bosons).
Matter composed of antiparticles with the same mass as their ordinary-matter counterparts but opposite charge; when matter meets antimatter, they annihilate, releasing energy as photons.
The Higgs field, which is theorised to give fundamental particles their mass through their interaction with it; discovered at CERN's Large Hadron Collider in 2012.
