Particles Revision Cards Flashcards
What is the nucleon number?
The number of protons and neutrons added together. Otherwise referred to as atomic mass.
What’s the charge of a proton and electron?
Proton = 1.6 x 10 - 19
Electron = - 1.6 x10 -19
What is the mass of a proton and neutron?
1.67 x10 -27
What is the mass of an electron?
9.11 x 10 -31
What is the relative mass of an electron?
0.0005
What do all atoms not have in common?
Atomic Number otherwise proton number.
What is the symbol for atomic number?
Z
What does the number of electrons define about the atom?
The elements reaction and chemical behaviour.
What does the proton number define about an atom?
Chemical properties
What is Nuclide Notation?
The diagram that is used to show or calculate the atomic number and mass number of elements.
What is the symbol of mass number?
A
Define Specific Charge?
Specific Charge is the atoms ratio of charge to its mass.
What is the units for specific charge?
C Kg -1
What is the equation for specific charge?
Specific charge = Charge / Mass
What is a fundamental particle?
A particle which cannot be split into smaller particles.
What is an isotope?
An atom with the same number of protons but a different number of neutrons.
What property does an isotope of an atom differ from the original atom?
The stability of the atoms nucleus.
What does a higher number of neutrons do to the nucleus?
Makes it more unstable and be more likely to be radioactive and decay.
What is isotopic data?
The amounts of different isotopes that are present.
How do you work out a specific charge question?
- Work out mass in the nucleus
- Work out charge in nucleus and add that to charge of electron
- Put these values in specific charge equation
What does electromagnetic force do to an atoms?
Causes positive charged protons in the nucleus to repel each other.
What does gravitational force do to the nucleus?
Causes all nucleons to attract to each other due to their mass.
What force is larger: Gravitational or Electromagnetic?
Electromagnetic
What is strong force?
A repulsive force at 0.5 fm and attractive at 3 fm. This force works at equal distances between all nucleons and gives the nucleus structure so it doesn’t collapse with the separation distances between the nucleons
What is nuclear decay?
When unstable nuclei emit particles to become more stable
What is alpha decay?
When an atom has its nucleon number decrease by 4 and its atomic number by 2.
What is the symbol for alpha decay?
α
What is the range of alpha particles?
A few cm in air.
What is the symbol for beta minus decay?
β–
What is beta minus decay?
When proton number increases by 1 and neutron number stays the same and produce an electron anti-neutrino
What is neutron rich?
Neutron Rich is where a nucleus has too many neutrons compared to protons.
Why does Beta Minus decay happen?
When an atom is unstable because it is neutron rich and ejects a neutron to a proton to become more stable. And the anti-neutrino and electron is produced to ensure proper conservation of energy.
Who significantly enhanced the research into beta minus decay and the anti-neutrino?
Wolfgang Pauli in 1930 when he gave evidence that went original theory of just electron produced because conservation of mass didn’t work and this left over energy was the anti-neutrino.
What is the electromagnetic spectrum?
The spectrum with all frequencies of electromagnetic radiation
What is frequency?
The number of waves that pass a point per second
What is wavelength?
Distance between 2 adjacent crests
What is the relationship in the electromagnetic spectrum between energy of a wave and its frequency?
The higher the frequency the more energy it has
What is the order of the electromagnetic spectrum?
Radio Waves -> Microwaves -> Infared -> Visible Light -> UV -> X-ray -> Gamma Rays
What did Max Planck study?
He studied black body radiation and suggested EM waves could only be released in packets
What are packets of EM waves also referred to as?
Quanta
What is the speed of light?
3x10-8 ms-1
What is the number of Planck’s constant?
6.63x10-34 Js
What is the equation to work out the energy of a photon?
E = hf
Energy = Plancks Constant x frequency
What is the equation to work out the frequency of an electromagnetic photon?
F = Hc/λ
Frequency = Planck’s Constant x Speed of Light / Wavelength
How do you resolve Planck’s Constant and frequency of a photon?
hf=hc/λ
Planck’s Constant x Frequency = Planck’s Constant x Speed of light / Wavelength
What does each particle have?
Each particle has a corresponding anti-particle
What is the substance which make particles and anti-particle?
Particles are made up of matter and anti-matter
How is an anti-particle defined?
A particle with the same mass and rest energy but a different charge
What is the rest energy and mass of a proton?
Rest Energy = 938.3 MeV
Mass = 1.673 x10 -27 kg
What is the rest energy of a neutron and it’s mass?
Rest Energy = 939.6 MeV
Mass = 1.675 x 10-27 kg
What is the rest energy and mass of an electron?
Rest Energy = 0.511 MeV
Mass = 9.11x10-31 kg
What is Einstein’s theory in relation to pair production?
Energy and Mass can be converted between the each other
What is the definition of pair production?
Pair Production is when energy is converted into mass and you get equal amounts of matter and anti-matter
What is two condition of pair production?
It can only happen if there’s enough energy to produce the particles mass.
Conservation of mass and energy of the anti-particles and particles has to happen
What happens if additional particles or anti-particles are created in pair production?
Their corresponding particle or anti-particle will be produced
What a higher energy photon in a pair production reaction: positron-electron pair or a proton anti-proton pair
Positron-electron pair
When are electron-positron pairs made?
Typically when a photon passes near a nucleus
What happens to an electron-positron pair produced in a detector?
Particles curves away in opposite directions because they are applied in a magnetic field and have opposite charges
Why is total rest energy significant in pair production?
It is the minimum energy to allow the pair production happen for the particles or antiparticles involved
What is rest energy?
The energy which is required to change the particles mass into energy
What is the symbol for rest energy and minimum energy for pair production?
Rest Energy = E 0
Minimum Energy in Pair Production = 2E 0
What is the equation for pair production?
Emin = 2E0
Minimum Energy in MeV = 2 x rest energy in produced particle
What is the typically most common pair in production?
Electron-Positron pairs as they have a relatively low mass and hence energy to interact successfully
What is annihilation?
When a particle meets and interacts with its antiparticle
What happens in the process of annihilation?
Mass of particles get converted into energy and produces 2 gamma ray photons
In annihilation why don’t antiparticles appear as ordinary matter?
They only exist for a fraction of a second before the annihilation process
What is the equation for annihilation?
E min = E 0
Minimum Energy of a single photon = rest energy of annihilated particle
How are Gamma Rays produced?
Gamma rays are produced in pairs and travel in opposite directions
How are protons held together?
They use strong force that make them repel each other and keep a stable separation distance
What are the particles that feel strong force?
Hadrons
What are the two types of hadrons?
Meson’s and Baryon’s
What are hadrons made up of?
Quarks
What are Sigmas?
Σ is the symbol for sigma particle and they are baryons that aren’t made up of ordinary matter as they contain strange particles
What is the only stable baryon?
A FREE proton
How do baryons end up as a free proton?
They get unstable and decay until they are in the stable baryon state of a free proton
What is the name of an anti-particle made baryon?
Anti-Baryon
Why aren’t anti-baryons made of ordinary matter?
This is because their antiparticle annihilates them
What is a quantum number?
A quantum number is a number which must be conserved in all interactions
What is the Baryon Number of baryons and anti-baryons?
Anti-Baryons = -1
Baryons =1
Non-Baron = 0
What happens to Baryon Number in decay interactions?
Remains Constant
What fundamental force causes Beta decay?
Weak Force
What is the equation for Beta Minus Decay?
n -> p + e+ νe (Line on Top)
What is another name for Beta-Minus decay?
Neutron Decay
What are the two types of Hadrons?
Baryons and Mesons
How to Mesons interact with Baryons?
Through the strong force
What are the lightest mesons?
Pions
What is the anti-particle of a hadron that has the power of 0?
Itself
For example π 0 has the anti-particle π 0
What are the exchange particles for strong force?
Pions
Name 2 properties of kaons?
Have a short lifespan and decay into pions
What are cosmic rays?
High energy particles constantly hitting the Earth
What are cosmic ray showers?
Where cosmic rays interact with particles in the Earth’s atmosphere and produce high energy particles in a reaction involving pions and kaons
How can cosmic ray showers be observed?
Using a cloud chamber and seeing if 2 Geiger Counter’s on top of each other detect simultaneously indicating a cosmic ray shower detected
What force are Leptons not affected by?
They are a fundamental particle which isn’t affected by strong force
What fundamental force do Leptons react with?
Weak Force
What happens to Leptons if they contain a charge?
If Leptons contain a charge they can react with Electromagnetic Force or Gravitational Force
What is the stable Lepton?
Electrons
What is the name of this hadron: μ?
Muon
What is a property of muons?
They are heavy electrons that are unstable and will eventually decay into an electron
What is one property of muons and electrons?
They both have their own neutrino and consequently seperate Lepton numbers
What is a property of neutrinos?
Have almost zero mass and no electric charge
What is the symbol for Strangeness?
S
How are strange particles created?
They are created by strong interactions but only made in pairs
What Hadrons do not have a strangeness?
Leptons
What is a property of strangeness?
Strangeness is conserved in only strong interactions
What are the only values strangeness can take?
-1,0,1
In all particle reactions what happens to momentum and the amount of energy and charge?
They are all conserved
What is the only way to change the composition of a hadrons quark structure?
Through weak interactions
What is the charge and baryon number of an UP quark?
The charge is + 2/3 and its baryon number is 1/3
What is the charge and baryon number of a DOWN quark?
The charge is -1/3 and its baryon number is 1/3
What is the charge and baryon number of a STRANGE quark?
The charge is -13 and its baryon number is 1/3
What does quark composition impact about a particle?
It changes its properties
What are antiquarks?
They are subatomic particle with the opposite charge of quarks
What are antiparticles?
Antiparticles are hadrons made of antiquarks
What is the quark composition of a baryon?
A baryon is always made up of 3 quarks
What is the quark composition of an antibaryon?
An antibaryon is made up of 3 antiquarks
Are Leptons made up of quarks?
Leptons are not made up of quarks
In terms of quark structure what is the difference between a proton and neutron?
A proton has a 2 Up quarks and a down quark whereas a neutron has 1 Up quark and 2 down quarks
What is the composition of a meson?
A meson is made up of one quark and antiquark
What is the composition of a pion?
A pion is only made up of up and down quarks and their respective antiquarks
Who predicted the existence of quarks?
Murray Gell-Mann predicted their existence in 1969
What is the structure of all the kaons?
K+ = Up Quark and an Anti-Strange
K- = Anti-Up and a Strange
Anti Kaon 0 = Anti-Down and a strange
K0 = Up quark and an Anti-strange
What is the structure of all pions?
π + = Up Quark and Anti-Down
π - = Down and Anti-Up Quark
π 0 = Up Quark and Anti Up
Down and an Anti-Down
Strange and Anti-Strange
What is Quark Confinement?
Where you cannot have a singular quark on its own. This is because the energy that is tried to remove quark makes an anti-quark of the quark trying to be removed.
What does Beta-Minus decay involve?
A neutron changing into a proton
What is the Quark Character?
Changing one quark into another quark
What is the Quark Character of weak interaction?
Weak interaction is the only interaction which can change a down quark into an up quark
What is an example of an element which goes through Beta Plus Decay?
Beta Plus decay happens in carbon-11 as well other unstable isotopes
How does Beta Plus decay differ from Beta Minus Decay?
Beta Plus decay releases a positron and electron neutrino whilst turning a proton into a neutron. Beta Minus decay releases an electron and electron anti-neutrino whilst turning a neutron into a proton
Who predicted the existence of anti matter?
Paul Dirac predicted the existence on antimatter in 1928
How was the neutrino hypothesised?
The neutrino was hypothesised as experiments saw conservation of mass and energy didn’t occur so must be a particle which completes this
How are all forces caused?
All forces are caused by particle exchange
What is instantaneous action?
When 2 particles exert a force on each other a process happens which alerts both particles of the others presence
When was the exchange particle discovered?
1983
What is the name of the particle that helps allow instantaneous action?
Exchange Particle
What is a repulsive force?
When particle initiating the interaction moves backwards and the colliding particle moving forwards
What is an attractive force?
When particle initiating the interaction moves forwards and the colliding particle moves backwards
What causes forces to act between 2 particles?
Exchange Particle
What is another name for exchange particles?
Gauge Boson or Virtual Particles
What are virtual particles?
Virtual Particles are particles which only exist for a very short amount of time and only exist long enough to transfer energy and momentum between particles
What is the name of the exchange particles that belong to fundamental forces?
Gauge Boson
What interactions affect each type of particle?
Strong Force = Hadrons Only
EM = Charged Particles
Weak Force = All types
What are the gauge bosons of interactions?
Strong = Pions
EM = Virtual Photon
Weak = W+ or W- boson
What impacts the size of the exchange particle?
Range of the force in the interaction
What is the relationship between exchange particles mass and their range?
As exchange particles get heavier they have a shorter range. As they get lighter they have a longer range
Why does weak force have such a short range?
W bosons are so heavy they are 100 times heavier than a proton so consequently have a short range
Why does the Virtual W Boson only exist for a short time?
It uses high amounts of energy
Why does EM have an infinite range?
It has zero mass
How are exchange particles represented in Feyman Diagrams?
Wiggly lines between the collision of each side of the colliding particles
How is the trajectory of colliding particles represented in Feyman Diagrams?
Straight Lines
What are the interactions which are shown on Feyman Diagrams?
Electromagnetic Force or Weak Force interactions
Where are baryons and leptons drawn on Feyman Diagrams?
Leptons on the right and Baryons stay on the left
What is the equation for electron capture?
p + e- -> n + νe
Why does electron decay happen?
A proton rich nucleus to become stable captures an electron and turns it into a neutron and an electron neutrino is released to conserve energy
What is the difference between electron capture and an electron proton collision?
Electron-Proton collisions have a W- boson going left whereas electron capture is a w+ boson going right
What is an electron proton collision?
Where an electron collides with a proton at high speed
What is Electromagnetic Repulsion?
When 2 particles of equal charge get close and repel. The exchange particle of this reaction a virtual photon
How do you go from electron volts to joules?
1 MeV = 1.6 x 10 ^19 Joules
