7 - Atomic, nuclear and particle Flashcards

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1
Q

What did Rutherford’s experiment show?

A

the atom is mostly empty space
the mass of the atom is within the nucleus
deflected beam of particles must have approached positively charged region - the nucleus
volume of nucleus is very small

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2
Q

What are electron energy levels?

A

specific energies electrons in an atom can have

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3
Q

What causes an electron to be excited?

A

absorption of energy

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4
Q

What causes an electron to be relaxed?

A

emission of energy

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5
Q

What is the ground state?

A

13.6eV - the lowest energy level

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6
Q

What is the first excited state?

A

3.4eV

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7
Q

What is the second excited state?

A

1.5eV

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8
Q

What is the ionisation level?

A

0eV - the highest energy level, at which, the electron can escape the atom, forming an ion

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9
Q

What is activity?

A

the number of nuclear disintegrations per second

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10
Q

What is activity measured in?

A

Bequerels, Bq

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11
Q

What is alpha decay?

A

an element decays to produce a different element and an alpha particle, consisting of two protons and two neutrons

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12
Q

What is gamma radiation?

A

an EM wave emitted due to transitions in the nucleus

often accompanies alpha and beta decay

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13
Q

What is beta + decay?

A

a proton decays into a neutron, a positron and a neutrino

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14
Q

What is beta - decay?

A

a neutron decays into a proton, an electron and an anti-neutrino

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15
Q

What is beta?

A

a fast moving electron

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16
Q

What is an electron volt?

A

a unit of energy
KE electron gains by travelling across a pd of 1 volt
1eV = 1.6x10^-19C

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17
Q

What is the equation for energy gain?

A

energy gain = voltage x charge

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18
Q

What is half-life?

A

the time for half the radioactive isotopes to decay

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19
Q

What are quanta?

A

discrete packets of the EM spectrum

measurement of quantity

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20
Q

What are photons?

A

the smallest discrete amount of EM radiation

elementary particle

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21
Q

What is the energy carried by quantum?

A
E = hf
h = Planck's constant 6.63 x 10^-34Js
f = frequency
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22
Q

What is an electronvolt?

A

an alternative unit of energy

the KE electron gains travelling across a pd of 1 volt

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23
Q

What is the equation for energy gain?

A

E = VQ

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24
Q

What is strong force?

A

the force which exists within the nucleus to hold protons and neutrons together

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25
Q

What is the mass defect?

A

the difference between mass of the nucleus and mass of the individual particles

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26
Q

What is the binding energy?

A

the energy needed to separate the nucleus into individual particles

27
Q

How does the binding energy of the particles change after nuclear fission?

A

heavier elements are split into lighter elements, with lower binding energy per nucleon

28
Q

How does the binding energy of the particles change after nuclear fusion?

A

lighter nuclei are joined to form a heavier nucleus with higher binding energy per nucleon

29
Q

What are the characteristics of hadrons?

A

affected by strong force
made of quarks
relatively heavy

30
Q

What are the characteristics of barions?

A

hadrons
made of three quarks
relatively heavy

31
Q

What are the characteristics of mesons?

A

hadrons
intermediate heaviness
made of one quark, one anti-quark

32
Q

What are the characteristics of leptons

A

not affected by strong force
indivisible
relatively light

33
Q

What is the charge on an up quark?

A

+2/3

34
Q

What is the charge on a down quark?

A

-1/3

35
Q

What is the charge on a strange quark?

A

-1/3

36
Q

What is the charge on an anti-up quark?

A

-2/3

37
Q

What is the charge on an anti-down quark?

A

+1/3

38
Q

What is the charge on an anti-strange quark?

A

+1/3

39
Q

Which quarks is a proton made out of?

A

u u d

40
Q

Which quarks is a neutron made out of?

A

u d d

41
Q

Which quarks is a pion+ made out of?

A

u /d

42
Q

Which quarks is a pion- made out of?

A

/u d

43
Q

Which quarks is a pion0 made out of?

A

either u /u or d /d

44
Q

Which quarks is a kaon+ made out of?

A

u /s

45
Q

Which quarks is a pion- made out of?

A

s /u

46
Q

Which quarks is a kaon0 made out of?

A

d /s

47
Q

Which quarks is a /kaon0 made out of?

A

s /d

48
Q

What is anti-matter

A

for each matter particle, there is corresponding anti-particle
same mass as corresponding particle but opposite charge
when a particle and anti-particle meet, they annihilate and produce two photons

49
Q

Which leptons are electrically charged?

A

electrons, muons and taons

50
Q

Which leptons have zero mass and zero charge?

A

electron neutrino
muon neutrino
tau neutrino

51
Q

What are leptons?

A

elementary particles

not affected by strong force

52
Q

What are the characteristics of strong force?

A
attractive forces between nucleons p-p and n-n
repulsive at ranges less than 1fm
range doesn't extent beyond a few nm
doesn't depend on charge of nucleus
readily saturated by surrounding nucleon
53
Q

What virtual particle is exchanged in gravitational force?

A

graviton

54
Q

What virtual particle is exchanged in electostatic force?

A

photon

55
Q

What virtual particle is exchanged in strong force?

A

gluon

56
Q

What virtual particle is exchanged in weak force?

A

W+, W-, W0 bosons

57
Q

What must be conserved for an equation to be possible?

A

charge, lepton number and baryon number

58
Q

Which force are neutrinos affected by?

A

weak force

59
Q

Which reactions conserve strangeness?

A

any involving strong force or weak force

60
Q

What does the x axis of a Feynman diagram represent?

A

time

61
Q

What does the y axis of a Feynamn diagram represent?

A

the space dimension

62
Q

What is an electron moving to the right equivalent to?

A

a positron moving to the left

63
Q

What does a squiggly line represent?

A

a photon

64
Q

What are the implications of quark confinement?

A

quarks cannot be directly observed as free particles

must remain bound to other quarks