3.2 Particles and Radiation Flashcards
Alpha decay
decay by emitting a Helium nucleus to become more stable
Annihilation
Particle and antiparticle meet, destroy eachother and emit radiation
Antibaryon
Hadron consisting of three antiquarks
Atomic number Z
Number of protons in an atom’s nucleus
Baryon
Hadron consisting of three quarks. The proton is the only stable baryon
Beta decay
when B- or B+ particles are emitted following decay of a neutron-rich or proton-rich nucleus
Conservation rules
Rule that: Baryon No., Lepton No. Charge, Energy, Momentum. Always conserved in interactions
When is strangeness conserved?
Strong interactions
How are strange particles created?
Strong interactions
How to strange particles decay?
Weak interactions
de Broglie hypothesis
Matter particles have a wave-like nature
de Broglie wavelength
Wavelength of a matter particle
deexcitation
process by which atom loses energy by photon emission as electron moves to lower energy level - inner shell
diffraction
spreading out of waves that pass through gap or near edge
diffraction grating
plate with close parallel slits on it
dispersion
splitting of beam of white light into colours by prism
electromagnetic interaction
force or interaction between 2 charged objects
electromagnetic wave
wavepacket or photon consisting of transverse electic and magnetic waves in phase and at right angle to eachother
excitation
process in which atom absorbs energy without becoming ionised when electron moves from inner shell to higher energy level in outer shell
energy
capacity to do work
energy levels
discrete energy levels that electrons take in shells of atom
gamma radiation
high energy photons emitted by unstable nuclei or produced in particle annihilations
ground state
lowest energy state of an atom
hadron
particles and anti that can interact through the strong interaction
ion
charged atom
ionisation
process of creating ions
isotopes
atoms of the same element with a different number of neutrons and the same number of protons
kaon
meson that has a strange quark and another quark
lepton
particles that cannot interact through the strong interation
matter waves
wave-like behaviour of particles
meson
hadron made up of a quark and an anti quark
muon
negatively charged lepton with a greater rest mass than the electron
neutrino
uncharged lepton with a lower rest mass than the electron
nucleon
N or P in nucleus
nucleon number
number of P’s or N’s in the nucleus
nuclide
type of nucleus with a particular number of P’s and N’s
photoelectric effect
emission of electrons from metal surface when surface is hit with light with photons of frequency greater than threshold frequency
photon
packet or ‘quantum’ of electromagnetic waves
pion
meson with a u or d quark and antiquark
pair production
gamma photon changed in a particle and corresponding antiparticle
strong interaction
interaction between two hadrons
strong nuclear force
attractive force between nucleons that holds the nucleons in the nucleus together
Continuous Spectrum
continuous range of colours
line emission spectrum
characteristic coloured lines due to discrete frequencies and corresponding wavelengths
line absorption spectrum
dark vertical lines against continuous range of colours
weak interaction
interaction between 2 leptons and between a hadron and a lepton
weak nuclear force
force responsible for beta decay
virtual photon
carrier of the electromagnetic force - no charge and zero rest mass
W boson
carrier of the weak nuclear force - can have positive or negative charge and have non zero rest mass
Antimatter
Antiparticles with same quantum values but opposite charge to corresponding particles
threshold frequency
minimum frequency of light that will cause the photoelectric effect
work function
minimum amount of energy needed by an electron to escape from a metal surface
exchange particle for weak interaction
W- or W+ boson
exchange particle for strong interaction
pion or gluon
exchange particle for electromagnetic interaction
virtual photon
exchange particle for gravitational interaction
graviton
property of strange particles
made through strong interaction and decay through weak interaction
when is strangeness conserved
conserved in strong interaction, not conserved through weak interaction
significance of neurtino in beta decay
conserve momentum, conserve lepton number
fluroescence
emission of visible photons after atoms deexcite
excited state
an atom which is not in its ground state - lowest energy state
nucleus
relatively small part of atom in centre, contains all of atom’s positive charge, most of mass concentrated here
electron capture
proton-rich nucleus captures inner shell electron, turns into neutron and releases electron neutrino - photon emitted when an electron fills the inner shell vacancy by moving to a lower energy shell
