Particles Flashcards
What is the diameter of a nucleus?
10^-15m (1 femtometer)
What is the atomic diameter?
10^-10m
What is an isotope?
Same number of protons different amount of neutrons
How do you calculate specific charge?
(charge of particle)/(mass of particle)
How do you calculate the charge of a particle?
(protons)x(charge of an electron)
How do you calculate mass of a particle?
(protons+neutrons)x(mass of proton or neutron)
What must you say about electrons when calculating specific charge of an ion?
Electron mass is negligible
What does the strong nuclear force do?
Provides an attractive force between nucleons(protons+neutrons)
What is the range of the strong nuclear force?
3fm
Why does the strong nuclear force repel at less than 0.5 femtometer
The nucleus would collapse
Why does the strong nuclear force attract between 1-3 fm
So the protons wont repel each other
Why does the strong nuclear force stop attracting and repelling past 3fm
That’s how big the nucleus is so it stops,
Prevents atoms from attracting each-other
Why does the electrostatic force only repel
Because protons repel each-other
When does alpha radiation occur?
Occurs with unstable large nuclei with too many protons and neutrons
What is the structure of an alpha particle?
2 protons, 2 neutrons
(4-Nucleon number)
How does alpha decay equations work?
Proton number decreases by 2
Nucleon number decreases by 4
When does beta decay occur?
With nuclei with too many neutrons
What does beta decay consist of?
Fast moving electron
What happens in the nucleus during beta decay?
A neutron decays into a proton and electron and an electron antineutrino
How do beta decay equations work?
Add 1 to proton number
Add a beta particle
Add an electron antineutrino
What is gamma radiation?
EM radiation emitted from an unstable nucleus
When does gamma radiation occur?
Straight after alpha or beta decay
Excess energy is released as gamma radiation
What is antimatter?
Name for all possible particles that have the same mass but opposite of all other properties to the normal matter
Whats the antiparticle for a neutron?
antineutron
Whats the antiparticle for a proton?
antiproton
Whats the antiparticle for a electron?
positron
What is the equation for annihilation?
E=mc^2
What is annihilation?
When a particle and its antiparticle meet and annihilate
All mass and kinetic energy is converted into two photons of equal frequency that move in opposite directions to conserve momentum
What is the equation for pair production
E(min)=2(mc^2)
What is pair production?
How antimatter is produced
Energy of one photon can be used to create a particle and corresponding antiparticle
Photon doesn’t exist after
What happens to excess energy in pair production
Turns into kinetic energy given to both particles
What is weak nuclear force?
Explains how beta decay occurs by affecting particles such as electrons, SNF does not
What is WNF exchange particle?
W+,W- and Z bosoms
What is SNF exchange particle?
Gluons
Pions
What is EM exchange particle?
Photons
What happens during beta minus decay?
Neutron decays into a proton and W- bosom
While within the nucleus(due to short range) the W- bosom decays into a beta-minus particle and antineutrino
What happens during beta plus(positron) decay?
Proton decays into a neutron and W+ bosom
While within the nucleus the W+ bosom decays into a beta-plus particle and neutrino
What is electron capture?
Occurs with proton rich nucleus
Excess protons interacts with inner shell electrons to form a neutron and neutrino
What does Rutherford’s experiment show about protons
The proton is not solid but mainly composed of smaller particles
What are protons and neutrons made up of
3 quarks
What are the 6 types of quarks
Top
Up
Down
Bottom
Charm
Strange
Why are quarks never found on their own?
Because they experience SNF and form groups of integer charge
What is a hadron?
Name for particles made up of quarks
Broken up into subgroups baryons and mesons
What are baryons?
Particles like protons and neutrons made up of 3 quarks
What are antibaryons
Particles like protons and neutrons made up of 3 anti-quarks
What is the quark structure for a proton?
UUD
What is the quark structure for a neutron?
UDD
What baryon number will baryons have?
+1
What baryon number will non-baryons have?
0
What baryon number will anti-baryons have?
-1
What is conserved during baryon equations?
Charge
Baryon number
What are the baryon numbers for protons, antineutrons, pi-mesons, sigma-minus, antineutrinos and neutrons?
Protons=1
Antineutrino=1
Pi-meson=0
Sigma-minus=1
Antineutrino=0
Neutron=1
What is the quark structure for a sigma-plus particle?
UUS
What is the quark structure for a sigma-(neutral) particle?
UDS
What is the quark structure for a sigma-minus particle?
DDS
What are mesons?
Particles made up of a quark, anti-quark pair
They are all unstable
What are mesons baryon number?
0
What are two types of mesons?
Pions(pi mesons)
Kaons(k mesons)
What are pions?
Unstable particles held together by SNF but decay by WNF
Lighter than protons but heavier than electrons
What are kaons?
Unstable particles that decay by WNF slower than pions
Why are kaons heavier than pions?
Because they have a strange/anti-strange quark and pions don’t
What can kaons decay into?
Pions, muons and neutrinos
What are leptons?
Fundamental particle(not made up of any other particle)
Have small masses
Integer charge(-1 or 1)
Mostly interact with WNF
What are some examples of leptons?
Electrons, electron neutrino
Muon, muon neutrino
What are electrons?
Stable, fundamental particles
Negative charge
What are muons?
Unstable, fundamental particles
Negative charge
What do muons decay into
Electrons and neutrinos
What are neutrino?
Leptons with no mass and charge
What is the electron lepton number for electrons and electron neutrinos?
+1
What is the electron lepton number for positron and anti-electron neutrinos?
-1
What is the electron lepton number for muon and muon neutrinos?
0
What is the muon lepton number for electrons and electron neutrinos?
0
What is the muon lepton number for positron and anti-electron neutrinos?
0
What is the muon lepton number for muon and muon neutrinos?
+1
What is the muon lepton number for anti-muon and anti-muon neutrinos?
-1
What does EM force do?
Mediates interactions between all charged particles but doesn’t cause any change in the arrangement or type of particles involved
What does SNF act on?
Acts between quarks and any particle made from a combination of quarks
What does Em force act on?
Acts between leptons and hadrons with a non-zero charge
What does SNF do?
-Mediates interacts between hadrons ONLY
-Can create quark-anti quark pairs and rearrange quarks between hadrons but not change quark type
-Allows pair production and annihilation to take place
What does WNF act pn?
All fundamental particles especially lepton interactions
What does WNF do?
Mediates interacts with charged and uncharged leptons
Responsible for decay of hadrons
