Particles and Radiation Flashcards
Alpha Decay
The process of an unstable nucleus emitting an alpha particle (two
protons and two neutrons) to become more stable.
Annihilation
The process of a particle and its antiparticle colliding and being
converted into energy. The energy is released in two photons to conserve momentum.
Antiparticle
All particles have a corresponding antiparticle with the same mass
but opposite charge and conservation numbers.
Baryon
A class of hadron, that is made up of three quarks. The proton is the only stable baryon.
Baryon Number
A quantum number that is conserved in all particle interactions.
Baryons have a baryon number of +1 and non-baryons have a baryon number of 0.
Beta-Minus Decay
The process of a neutron inside a nucleus turning into a
proton, and emitting a beta-minus particle (an electron) and a antineutrino.
Beta-Plus Decay
The process of a proton inside a nucleus turning into a
neutron, and emitting a beta-plus particle (a positron) and a neutrino.
Electron Diffraction
The spreading of electrons as they pass through a gap
similar to the magnitude of their de Broglie wavelength. It is evidence of the wave-like properties of particles.
Electron-volt (eV)
The work done to accelerate an electron through a potential
difference of 1V. 1eV is equal to the charge of an electron (E=qv).
Energy Levels
Defined and distinct energies at which electrons can exist in an
atom. An electron cannot exist between energy levels.
Excitation
The process of an electron taking in exactly the right quantity of
energy to move to a higher energy level.
Ground State
The exchange particles that transmit the four fundamental
interactions between particles.
Gauge Boson
The most stable energy level that an electron can exist in.
Hadrons
A class of subatomic particle that experiences the strong nuclear
interaction.
Ionisation
The process of an atom losing an orbital electron and becoming charged.
Isotope
Same number of protons but different numbers of neutrons.
Isotopic Data
Data from isotopes that can be used for a purpose, such as carbon dating.
Kaon
A type of meson that decays into pions.
Lepton Number
A quantum number that is conserved in all particle interactions.
Both electron lepton numbers and muon lepton numbers must be conserved.
Lepton
A group of elementary subatomic particles, consisting of electrons,
muons and neutrinos.
Meson
A class of hadron that is made up of a quark and antiquark pair.
Muon
A type of lepton that decays into electrons.
Neutrino
A subatomic particle whose existence was hypothesised to maintain the conservation of energy in beta decay.
Nucleon Number (A)
The sum of the number of protons and neutrons in a given nucleus.
Nucleon
A proton or neutron.
Pair Production
The process of a sufficiently high-energy photon converting into
a particle and its corresponding antiparticle. To conserve momentum, this usually occurs near a nucleus.
Photon
A packet of energy.
Pion
A type of meson and the exchange particle for the strong nuclear force.
Positron
A positively charged particle that is the antiparticle of an electron.
Proton Number (Z)
The number of protons present in the nucleus of a given element
Stopping Potential
The minimum potential difference required to stop the
highest kinetic energy electrons from leaving the metal plate in the photoelectric effect.
Strange Particles
Particles that are produced through the strong interaction but
decay through the weak interaction.
Strangeness
A quantum number that is conserved in strong interactions but not
in weak interactions. This reflects that strange particles are always produced in pairs.
Strong Nuclear Force
A force that acts between nucleons in a nucleus to keep it
stable. It is attractive at distances of up to 3fm and repulsive at separations less than 0.5fm.
Threshold Frequency
The minimum frequency of photons required for
photoelectrons to be emitted from the surface of a metal plate through the photoelectric effect. It is equal to the metal’s work function divided by Planck’s constant
Work Function
The minimum energy required to remove an electron from a metal’s surface.
