Particles Flashcards
1
Q
What are the three constituents of an atom? (3)
A
Proton, Neutron, Electron
2
Q
What is the relative mass of a Proton?
A
1
3
Q
What is the relative mass of a Neutron?
A
1
4
Q
What is the relative mass of an Electron?
A
1/1830
5
Q
What are the units for Specific Charge?
A
CKg-1
6
Q
What is the equation for Specific Charge?
A
Q/m
7
Q
What is a Nucleon?
A
A particle in the nucleus
8
Q
What are Isotopes?
A
Versions of the same element, they have the same proton number but different number of neutrons
9
Q
What is another name for the Mass Number?
A
Nucleon number
10
Q
What is another name for the Proton Number?
A
Atomic number
11
Q
What is the Strong Nuclear Force?
A
An attractive force between nucleons
12
Q
What is the range of the Strong Nuclear Force?
A
~ 3 fm
13
Q
What does Strong Nuclear force do in an atom?
A
Overcomes the repulsion between positive protons and holds the nucleus together
14
Q
What does the strong nuclear force do at short ranges?
A
Becomes a repulsive force
15
Q
At what range does strong nuclear force become repulsive?
A
~ 0.5 fm
16
Q
Why does the strong nuclear force become repulsive at close range?
A
To stop the nucleus from collapsing in on itself
17
Q
What is an alpha particle made up of? (2)
A
2 Protons, 2 Neutrons
18
Q
What is an Alpha Particle the same as?
A
A helium nucleus
19
Q
How fast is an Alpha compared to Gamma and beta?
A
Slowest
20
Q
What is the charge of an Alpha Particle?
A
2+
21
Q
What does the 2+ charge mean an Alpha is?
A
Strongly ionising
22
Q
What is a Beta Particle?
A
1 electron
23
Q
How fast is Beta compared to Alpha and Gamma?
A
Faster not fastest
24
Q
What is the charge of a Beta Particle?
A
-1
25
What do we write for Beta's atomic/proton number?
-1
26
What does the -1 charge mean a Beta Particle is?
Weakly ionising
27
How does a Beta Particle ionise?
By pushing/repelling electrons off atoms
28
How is a Beta Particle created?
A neutron turns into a proton and an electron (beta)
29
n -> ? + ?
p + β
30
Where does Beta Decay occur?
Proton rich nuclei
31
Where does Alpha Decay occur?
Large Nuclei
32
Which type of decay happens in neutron-rich nuclei?
β-, neutron emitter
33
Which type of decay happens in proton-rich nuclei?
β+, electron capture
34
How are Alpha Particles emitted from the nucleus?
The repelling of the other protons overcomes the strong nuclear force and pushes it out
35
In a Cloud Chamber what qualities do Alpha trails share, and why?
Length, because all alpha have the same kinetic energy
36
For Beta trails, do they share length, and why?
They don't share length, they have varying kinetic energy, but the parent nucleus still loses the same energy
37
What explains the extra energy lost in Beta Decay?
The antineutrino
38
What qualities do corresponding Particles and Antiparticles share?
Rest mass and rest energy
39
What qualities do corresponding Particles and Antiparticles do not share?
Charge, baryon, lepton and strangeness numbers are opposite
40
What is an electron volt (eV)?
The work done by an electric field when accelerating an electron through a potential difference of 1 volt
41
Is an eV big or small?
Small
42
How many eVs are in 1MeV?
1 million
43
Rest energy is the energy equivalent to what?
Rest mass (when converted into energy)
44
What is the Electromagnetic Spectrum in order?
Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma ray
45
What is the longest wave length in the EM spectrum?
Radio
46
What is the shortest wavelength in the EM spectrum?
Gamma ray
47
What on the EM spectrum has the lowest frequency?
Radio waves
48
What on the EM spectrum has the highest frequency?
Gamma rays
49
Speed of light in a vacuum?
300 x 10^8 ms^-1
50
What happens in Pair Production?
Energy is converted into mass in the form of a particle-antiparticle pair
51
Where does the energy come from in Pair Production?
A collision or gamma photon
52
p (momentum) = ?
m (mass) x v (velocity)
53
What can a Gamma Photon spontaneously do and where does this occur?
Convert its energy into mass in the form of a particle-antiparticle pair. Usually happens near a nucleus which then recoils to conserve momentum
54
What is Annihilation?
Where a particle meets its antiparticle counterpart and they convert their mass into energy into the form of a pair of gamma photons
55
What are the 4 fundamental interactions?
Strong nuclear (or strong interaction), weak nuclear, electromagnetic (including electrostatic), gravity
56
What are the Exchange Particles for Strong Nuclear Force?
Pions
57
What are the Exchange Particles for Weak Nuclear Force?
Bosons W+ W-
58
What are the Exchange Particles for Electromagnetic Force?
Virtual photon
59
What is the Exchange Particle for Gravity?
Graviton
60
What do Exchange Particles do?
Pass between particles to carry the force, energy, charge and momentum across
61
What is the Exchange Particle when a Proton and an Electron are attracted to each other?
Virtual photon
62
The smaller the mass of the Exchange Particle the...?
Greater the range of the force
63
Can Exchange Particles be overcome by more of a different exchange particle? If so give an example of this
Yes, e.g. in a nucleus pions can attract more than virtual photons repel (not always)
64
What is the equation for beta- decay?
n -> p + β- + (anti)νe
65
In a Feynman diagram what is usually on the left and what is usually on the right?
Left is baryons, right is leptons
66
What is always conserved at the junctions in a Feynman diagram?
Charge, baryon and lepton numbers
67
In a Feynman diagram for beta- decay what goes into and what comes out of the first junction? And what direction does the exchange particle go in?
Neutron goes in, proton and W- exchange particle goes out. W- to the right
68
In a Feynman diagram for beta- decay what goes into and what comes out of the second junction?
W- exchange particle goes in, β- and a (anti)νe (antineutrino) comes out
69
What is the equation for β+ decay?
p -> n + β+ νe
70
In what sort of nucleus does beta+ decay occur?
Proton-rich
71
In a Feynman diagram for beta+ decay what goes into and what comes out of the first junction?
Proton goes in, neutron and W+ exchange particle comes out
72
In a Feynman diagram for beta+ decay what goes into and what comes out of the second junction?
W+ exchange particle goes in, β+ and νe comes out
73
What happens in Electron-capture?
An inner shell electron is captured by a proton in the nucleus (becoming a neutron)
74
What is the equation for Electron-capture?
p + e- -> n + νe
75
In what sort of nucleus does Electron capture occur?
Proton-rich
76
In a Feynman diagram for electron capture what goes into and what comes out of the first junction? And what direction is the exchange particle in?
Proton goes in, neutron and W+ exchange particle comes out. W+ to the right
77
In a Feynman diagram for electron capture what goes into and what comes out of the second junction?
W+ exchange particle and e- goes in, νe comes out
78
W+ to the right is the same of what?
W- to the left
79
What happens in proton-electron collision?
A proton and electron colide
80
What sort of nucleus does proton-electron collision happen in?
A stable one
81
The Feynman diagram for proton-electron collision is the same as what?
Electron capture
82
What is a hadron and what are they composed of?
They are composed of quarks and antiquarks, they experience the strong interaction/ strong nuclear force
83
What are the types of hadron? (3)
Baryons, antibaryons, mesons
84
Name the baryons
Protons and neutrons
85
What are baryons made up of?
3 quarks
86
What are the baryon numbers for protons and neutrons?
+1
87
What are the Antibaryons? (2)
Antiproton antineutron
88
What are the antibaryons made up of?
3 antiquarks
89
What are the baryon numbers for antiprotons and antineutrons?
-1
90
What are the mesons?
Pions and kaons
91
What are mesons made up of?
A quark and antiquark pair
92
What is special about a proton?
It's the only stable baryon into which other baryons eventually decay
93
What is the baryon number all of mesons?
B = 0, they aren't baryons
94
What can a kaon do?
Decay into a pion
95
What is a kaon?
A strange particle
96
What is a lepton?
A particle that doesn't experience the strong interaction/ strong nuclear force
97
What are the leptons that aren't neutrinos?
Electron (e-), positron (e+), muon (μ-) and antimuon (μ+)
98
What are the leptons that are neutrinos?
Electron neutrino (νe), electron antineutrino (νe, with a bar), muon neutrino (νμ), muon antineutrino (νμ, with a bar)
99
What are the two types of lepton number?
Electron lepton number (Le) and muon lepton number (Lμ)
100
What is the Le of an electron?
+1
101
What is the Le of a positron?
-1
102
What is the Le of a muon and antimuon?
0, not electron leptons
103
What is the Lμ of an electron and positron?
0, not muon leptons
104
What is the Lμ of a muon?
+1
105
What is the Lμ of an antimuon?
-1
106
What is the Le of an electron neutrino?
+1
107
What is the Le of an electron antineutrino?
-1
108
What is the Le of a muon neutrino and an antimuon neutrino?
0
109
What is the Lμ of an electron neutrino and an electron antineutrino?
0
110
What is the Lμ of a muon neutrino?
+1
111
What is the Lμ of a muon antineutrino?
-1
112
What is the Le and Lμ of hadrons?
0
113
What does a muon decay into?
An electron
114
What do strange particles contain?
Strange or antistrange quarks
115
What type of particle are strange particles?
Hadrons
116
Strange particles are produced in what?
Strong interactions
117
Strange particles decay via what?
Weak interactions
118
Strong interactions must conserve what?
Strangeness
119
Strange particles are always produced in what, why?
Pairs of s=+1 and s=-1, because strangeness is always conserved in strong interactions
120
Do weak interactions have to conserve strangeness?
No. Can change by +1 -1
121
What is the strangeness of a K+ and K0 particle?
+1
122
What is the strangeness of a K- and a K0(with a bar)?
-1
123
What are the types of quark?
Up, down, strange
124
What are the charges a quark can have?
Q(charge) = +2/3e (+2/3 of an electron) or Q = -1/3 (-1/3 of an electron)
