Particles Flashcards

1
Q

what are the 3 constituents that makes up an atom

A

protons neutron and electrons

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2
Q

what is found at the center of an atom and what is it made up of

A

a nucleus and is made up of protons and neutrons

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3
Q

what are protons and neutrons also known as

A

nucleons

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4
Q

where are electrons found in an atom

A

they are found in shells orbiting the nucleus

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5
Q

what is the charge of a proton neutron and electron

A

proton - +1.6x10^-19
electron - -1.6x10^-19
neutron - 0

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6
Q

what is the relative charge of a proton neutron and electron

A

proton - +1
electron - -1
neutron - 0

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7
Q

what is the mass of a proton neutron and electron

A

proton and neutron - 1.67x10^-27
electron - 9.11x10^-31

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8
Q

what is the relative mass of a proton neutron and electron

A

proton and neutron - 1
electron - 0.0005

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9
Q

what is the specific charge of a proton neutron and electron

A

proton - 9.58x10^7
neutron - 0
electron - 1.76x10^11

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10
Q

what are the units for specific charge

A

CKg^-1

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11
Q

what is the specific charge of a particle and how do you calculate it

A

the charge-mass ratio and is calculated by dividing a particles charge by its mass

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12
Q

what is an isotope

A

are atoms with the same number of protons but different numbers of neutrons

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13
Q

what is an example of an isotope

A

carbon-14 is a radioactive isotope of carbon which can be used to find the approximate age of an object containing organic material. this is done through carbon dating, which involves calculating the percentage of carbon-14 remaining in the object, and using the known starting value of carbon-14 and its half life to calculate an approximate age

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14
Q

how does the strong nuclear force keep the nuclei stable

A

by counteracting the electrostatic force of repulsion between protons in the nucleus(as they have the same charge). it only acts on nucleons and has a very short range, where it is attractive up to separations of 3 fm, but repulsion below separations of 0.5 fm,

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15
Q

what causes an unstable nuclei

A

when an atom has too many of either protons, neutrons or both causing the SNF to not be enough to keep them stable, therefore these nuclei will decay in order to become stable. the type of decay the nuclei will experience depends on the amount of each nucleon in them

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16
Q

where does alpha decay occur

A

in a large nuclei, with too many of both protons and neutrons

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17
Q

in the equation for alpha decay what happens to the proton number and nucleon number

A

the proton number decreases by 2
the nucleon number decreases by 4

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18
Q

where does beta minus decay occur

A

in nuclei which are neutron-rich (have too many neutrons)

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19
Q

what happens the the proton number and nucleon number in the equation for beta minus decay

A

the proton number increases by 1
the nucleon number stays the same

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20
Q

how did scientists theorize that there is a neutrino in beta minus decay

A

at first, scientists believed that only an electron was emitted from the nucleus during beta minus decay, however observations of the energy levels of the particles before and after the decay showed that energy was not conserved. this does not follow the principle of conservation of energy, and therefore neutrinos were hypothesized to account fir this, and later they were observed

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21
Q

what is there for every type of particle

A

an antiparticle

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22
Q

what do antiparticles have the same as the particle

A

the same rest energy and mass but all other properties are opposite

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23
Q

what is the antiparticle of an electron and neutrino

A

positron and antineutrino

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24
Q

what do electromagnetic radiation travel in

A

packets called photons which transfer energy and have no mass

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25
what is the energy of photons directly proportional to
the frequency of electromagnetic radiation
26
what equation shows that the energy of photons is directly proportional to the electromagnetic radiation
E = hf = (hc/lambda)
27
what is the value of plancks constant
6.63x10^-34 Js
28
what is annihilation
is where a particle and its corresponding antiparticle collide, as a result their masses are converted into energy
29
what is the energy during annihilation released as
is released in the form of two protons moving in opposite directions in order to conserve momentum
30
what is an application of annihilation and how does it work
is used in a PET scanner this allows 3D images of the inside of the body to be taken, therefore making medical diagnoses easier. this is done by introducing a positron-emitting radioisotope into the patient, as positrons are released they annihilate with electrons already in the patients system, emitting gamma photons which can easily be detected
31
what is pair production
is where a photon is converted into n equal amount of matter and antimatter. this can only occur when the photon has an energy greater than the total rest energy of both particles, any excess energy is converted into kinetic energy of the particles
32
what are the 4 fundamental forces
gravity electromagnetic weak nuclear (WNF) strong nuclear (SNF)
33
what are forces between particles caused by
exchange particles
34
what do exchange particles do
they carry energy and momentum between the particles experiencing the force and each fundamental force has its own exchange particles
35
if the interaction is strong what is the exchange particle, range and what does it act on
exchange particle - gluon range - 3x10^-15 acts on - hadrons
36
if the interaction is weak what is the exchange particle, range and what does it act on
exchange particle - W boson (W+ OR W-) range - 10^-18 acts on - all particles
37
if the interaction is electromagnetic what is the exchange particle, range and what does it act on
exchange particle - virtual photon range - infinite acts on - charged particles
38
if the interaction is gravity what is the exchange particle, range and what does it act on
exchange particle - graviton range - infinite acts on - particles with mass
39
what is the nuclear force responsible for
beta decay, electron capture, and electron-proton collisions all of which can be represented as the particle interaction diagrams
40
what is the equation for electron capture and electron-proton collision
- p + e- --> n + Ve
41
what is different about electron capture and electron-proton collisions
they have different exchange particles
42
what is the equation for beta plus decay
p --> n + e+ +Ve
43
what is the equation for beta minus decay
n --> p + e- + -Ve
44
what are all particles classified as
either hadrons or leptons
45
what is the difference between leptons and hadrons
leptons are fundamental particles
46
what classifies a particles as a fundamental particle
they cannot be broken down any further and they do not experience a strong nuclear force
47
what are hadrons formed from
quarks
48
what can hadrons be further separated into
baryons, antibaryons and mesons
49
what are baryons formed of
3 quarks
50
what are antibaryons formed of
3 antiquarks
51
what are mesons formed from
a quark and a antiquark
52
what does the baryon number show
shows whether it is a baryon (if 1), an antibaryon (if -1), or not a baryon (if 0)
53
what is the only stable baryon
a proton, therefore all baryons will eventually decay into a proton either directly or indirectly
54
what does the lepton number show
shows whether it is a lepton (if 1), antilepton (if-1) and not a lepton (if 0)
55
what are the two types of lepton numbers
electron lepton number muon lepton number
56
are baryon numbers and lepton numbers conserved in particle interactions
yes
57
what is a muon also known as and what does it decay into
a 'heavy electron' and decays into an electron
58
what are strange particles
are particles which are produced by the strong nuclear interaction but decay by the weak interaction
59
what are the strange particles you need to know about
a kaon which decay into pions through the weak interaction
60
what is strangeness
is a property of particles which shows that strange particles must be created in pairs, as strangeness must be conserved in strong interactions however in weak interactions strangeness can change by 0,+1,-1
61
what is needed to investigate particle physics but what are the cons
particle accelerators however they are expensive to build and run and also produce high amounts of data, scientific investigations rely on collaboration of scientists internationally
62
what are quarks
are fundamental particles which make up hadrons
63
what are the three types of quarks
up, down, strange
64
what is the charge baryon number and strangeness of an up quark
charge - +2/3e baryon number - +1/3 strangeness - 0
65
what is the charge baryon number and strangeness of a down quark
charge - -1/3e baryon number - +1/3 strangeness - 0
66
what is the charge baryon number and strangeness of a strange quark
charge - -1/3e baryon number - +1/3 strangeness - -1
67
when quarks combine what do they form
baryons and mesons
68
how do you find the quark combination of an antibaryon
if you know the quark combination of the baryon is to simply change the quarks into their respective antiquarks. also true for mesons
69
as all baryons decay into protons what else will decay into a proton
a neutron
70
what is the equation for neutron or baryon decay
n --> p + e- + -Ve
71
what properties must always be conserved in particle interactions
-energy and momentum -charge -baryon number -electron lepton number -muon lepton number
72
what is conserved in only strong interactions
strangeness
73
how do you show these conservation laws are obeyed in an interaction
you must find the value of each property before and after the interaction and make sure they are equal
74
what causes beta minus and beta plus decay
by the weak interaction because there is a change in quark type
75
in beta minus decay what must happen to the quark in order for a neutron to become a proton
a down quark must change into an up quark
76