Particles And Waves Flashcards
Antiparticles
For every particle there is another particle known as an antiparticle
The antiparticle has the same mass but a range of opposite effects
Antiparticles join together in the same way particles join to form matter
Posetron
(Positive electron)
The antiparticle to a negative electron
Negative anti-proton
The antiparticle to a positive proton
What do we call the 12 fundamental particles
Fermions
What two groups can fermions be split into
Quarks and leptons
Along with quarks and leptons there are 4
Bosons
Name the 1st generation quarks
Up quark
Down quark
Name the 2nd generation quarks
Charm quark
Strange quark
Name the 3rd generation quarks
Top quark
Bottom quark
Name the 1st generation leptons
Electron neutrino
Electron
Name the 2nd generation leptons
Muon neutrino
Muon
Name the 3rd generation leptons
Tau neutrino
Tau
Which fermions have a charge of 2/3
Up quark
Charm quark
Top quark
Which fermions have a charge of -1/3
Down quark
Strange quark
Bottom quark
Which fermions have a charge of 0
Electron neutrino
Muo neutrino
Tau neutrino
Which fermions have a charge of -1
Electron
Muon
Tau
Name the 4 bosons
Photon
Gluon
Z boson
W boson
What is a hadron
A particle made of quarks
Baryons
Made up of three quarks
Mesons
Made of a quark and an anti quark
Give two examples of baryons
Proton (UUD)
neuron (UDD)
Mesons
Made of a quark and antiquark pair
Because of this they are very unstable
Give an example of a meson
A pion is made of an up quark and a down anti-quark and is positively charged
Lepton
Fundamental particle (ie can’t be split into smaller particles)
Neutrons
Have no charge as they have never interacted with other particles
Produced in a variety of iterations, especially in particle decay
Initially discovered in radioactive beta decay
Beta decay
A neutron decays into a proton and electron
In order for momentum to be conserved another particle must be emitted
This is a tau anti-neutrino
the universe contains not only matter but…
forces
what causes action (forces) to take place
it is thought that attraction or repulsion acts by exchanging particles
exchange particles are called…
Bosons
pauli’s exclusion principle
two or more identical fermions (particles with half-integer spin) cannot occupy the same quantum state within a quantum system simultaneously (bosons do not follow this)
what is the exchange particle of a strong force
gluon
what is the exchange particle of electromagnetic exchange
photon
what is the exchange particle of a weak force
w and z
what is the exchange particle of gravitational exchange
graviton
describe a gluon
holds quarks together in baryons and mesons, acts between them
describe a photon
a particle like wave, holds electrons in atoms
w+, w- and z*
acts on quarks and leptons. involved in beta decay
describe the effects and limits of gravity
its affected by gravitons (yet to be discovered), it acts on everything, and its range has no limit
describe the effects and limits of weak electromagnetic forces
its affected by w+, w- and z* , it acts on quarts and leptons, and its range is 10^-17m but when affected by photons it acts on quarts and charged leptons and w+, w- and its range has no limit
describe the effects and limits of strong forces
its affected by gluons, it acts on quarts and gluons, and its range is 1x10^-15m
describe the Higgs field
effects different particles in different ways, photons can slide through unaffected while w and z bosons get bogged down by mass. assuming that it exists everything that has mass does so by passing through the all powerful higgs field.
Higgs Boson
like other field in the standard model, the higgs field would need a carrier particle to affect other particles , this is the higgs boson
name four sources of uncertainties
calibration uncertainty
reading uncertainty
random uncertainty
systematic effects
calibration uncertainty
when using measuring instruments there will always be error for example when using a meter stick: +/- 0.5mm
this means any reading is only accurate within +/- o.5mm
scale reading uncertainty
gives an estimate of how accurately a scale can be read
e.g analogue scale = +/- 1/2 smallest division
digital scale= +/- smallest division
random uncertainty
to give an estimate of how much our repeated values have deviated from the mean values
systematic effects
often caused by a fault in the measuring implement, or a problem with the method used.
Electron feild
The region around an electron change
In an electric field, an electric charge experiences a
Force
Electric field strength
A measure of the force on a unit charge
Work done =
QV
When a charged is moved between two points in an electric field….
Work is done
The charge of an object is measured in
coulombs
Magnetic fields exist around…
Moving charges
The force exerted on a charge is always…to the velocity of the charge
Perpendicular
The force exerted on a charge changes the velocity and so…
The direction of the applied force as a result
This results in circular motion
What are the three main types of particle accelerators
Linear accelerators
Cyclotrons
Synchrotrons
Name some basic parts of a particle accelerator
A source of particles Beam pipes (vacuum chambers) Accelerating structures A system of magnets A target
Describe a source of particles in a particle accelerator
May come from accelerator
Accelerators using electrons use thermionic emission
At CERN the source is a bottle of hydrogen gas. The electrons are stripped leaving positively charged protons
Describe a beam pipe in a particle accelerator
Special pipes in which the particles travel through while being accelerated
The vacuum inside the pipes ensures that the beam particles do not collide with other atoms such as air molecules
Describe accelerating structures in a particle accelerator
Particles enter a special area where there is a rapidly changing electric field
As protons approach the field is negative and protons accelerate. As they move aaa the field becomes positive and the protons are repelled
Describe a system of magnets in a particle accelerator
Particles in beam pipes would go in a straight line if they were not constantly going past powerful fixed magnets.
The magnets work best at absolute 0
Describe a target in a particle accelerator
In some accelerators the beam collided directly with a stationary target, such as a metal block
In the LHC the target is a bunch of particles travelling in opposite directions
Radioactive decay
The breakdown of a nucleus to release energy and matter from the nucleus
This allows stability to be achived
Radioisotopes (radionuclides)
Unstable nuclei
Alpha particles
4/2He
Helium nucleus
Beta particle
0/-1e
Fast electron
Gamma ray
High frequency electromagnetic wave
Describe alpha decay
Occurs in heavy nuclei (uranium, plutonium)
Major part of radioactive fallout
Relatively more massive so less penetrating
If an alpha decaying element in ingested it can do considerable damage
Describe beta decay
Occurs when an atom has too many protons or neutrons in its nucleus
Positive beta decay releases a positron and neutrino
Negative beta decay releases an electron and anti neutrino
These are high energy elementary particles released in order to conserve energy
Describe gamma decay
Results from the registration of electric charge within a nucleus
Essentially very energetic x-rays but instead of being emitted during atomic processes involving energetic electrons gamma radiation is emitted by excited nuclei or other processes involving sub atomic particles
More penetrating but less ionising
Produce burns, cancer and genetic mutations
Nuclear fission
When a heavy nucleus disintegrates , forming two nucleus of smaller mass number
It can be spontaneous or induced by neutron bombardment
Why is energy released in nuclear fission
Mass is a form of energy , when there is a decrease in mass an equivalent amount of energy is produced
This can be calculated by E=Mc^2
Nuclear fusion
Nuclear energy is also released by the fusion of two light elements
There is no limit to the amount of fusion that an occur
Very high temperatures are needed
To sustain fusion the conditions that must be met are;
Extremely high temperatures (T): 100-200 million K
A stable reaction lasting 5 seconds (energy confinement time (t))
A precise plasma density of around 10^20 particles/ m3
Name the main parts of a nuclear fission reactor
Fuel rods Moderator Control rods Coolant Containment vessel
Describe fuel rods in a fusion reactor
Pellets of enriched uranium are stacked in a rod, the mass below critical mass and the rods are grouped to form elements
Describe a moderator in a fusion reactor
Graphite water or heavy water surrounds the uranium elements so neutrons passing between elements can be slowed by collision
Describe control rods in a fusion reactor
Made of boron
Can be lowered or raised between the fuel rods to absorb neutrons
They are lowered to reduce the chain reaction or raised to meet the demand
Describe coolant in a fusion reactor
Removes heat
A pressurised liquid or gas such as water or carbon dioxide
Energy is passed through a heat exchanger to a turbine and electrical generator
Describe a containment vessel in a fusion reactor
The reactor is surrounded by a large steel lining and concrete to absorb radiation in an accident or in the event of natural disaster
Photoelectric effect
Under certain circumstances an electrically charged object can be made to discharge by shining electromagnetic radiation at it
Only if it is negatively charged and the radiation is of a sufficiently high frequency
Wave particle duality
Light can act as both a wave and a particle
E=hf
E= energy of photon (J)
f= frequency of photon (Hz)
h=Planks constant (6.63x10^-34 Js)
The thread hold frequency (f°) for each metal is….
Different
Increasing the frequency will not increase
The number of photo electrons
Increasing the frequency will increase
The speed at which the photo electrons eject
Increase the number of photos will…
Increase the number of photo electrons
The name given to the small amount of energy required to bring an electron to the surface of a metal and free it is …
The work function
Work function =
E°=hf°
Irradiance =
P N x hf
__=________=Nhf
A 1
What is meant by a wave that is in phase
Two points on a wave that are vibrating in exactly the same way at the same time
What is meant by a wave that is exactly out of phase
Two waves vibrating crest to trough at the same time
Coherent sources
Two sources that are oscillating with a constant phase relationship
Have the same frequency
When two coherent waves in phase meet….
Constructive interference occurs
When two coherent waves out of phase meet..
Destructive interference occurs
Interference is evidence for….
The wave model of light
Constructive interference occurs when…
Path difference= mλ
Destructive interference occurs when
Path difference= (m+1/2)λ
Continuous spectra
All frequencies of radiation are present in the spectrum. The continuous spectrum colours are red, orange, yellow, green, blue, indigo, violet
Line emission spectra
Emitted by excited atoms in a low pressure gas. Each element emits it’s own unique line spectrum
Lines on emission spectrum made by electrons making the transition from high energy levels to low energy levels. When an excited electron drops it releases a photon of a specific frequency that corresponds to a line on the spectrum
Absorbtion spectra
Energy absorbed from electrons is emitted as a photon of the same energy and frequency as the one absorbed, but it is unlikely to be emitted in the same direction. Therefore the spectrum will show black absorbtion lines
Farenhofer lines
The absorbtion lines in the absorbtion spectra of sunlight
