Particle & Nuclear Physics

Question 1

what are the two types of particles?

Answer 1

leptons and hadrons

Question 2

how do you make a proton?

Answer 2

uud

Question 3

how do you make an antiproton?

Answer 3

ūūd̄

Question 4

how to make a neutron?

Answer 4

udd

Question 5

how to make an antineutron?

Answer 5

ūd̄d̄

Question 6

what are the 6 types of quarks?

Answer 6

up, down, charm, strange, top, bottom

Question 7

what are hadrons?

Answer 7

anti/baryons and mesons

Question 8

what are examples of hadrons?

Answer 8

proton and neutron

Question 9

what are examples of anti-hadrons?

Answer 9

anti-proton and anti-neutron

Question 10

what are examples of mesons?

Answer 10

π⁰, π+ and π−

Question 11

how to make a π⁰?

Answer 11

uū
dd̄

Question 12

how to make a π+?

Answer 12

ud̄

Question 13

how to make a π−?

Answer 13

ūd

Question 14

how to make a π−?

Answer 14

ūd

Question 15

what are examples of baryons?

Answer 15

protons and neutrons

Question 16

what happens when 2 electrons interact?

Answer 16

virtual photon exchange particle creates a repulsive force

Question 17

what happens when two oppositely charged particles interact?

Answer 17

virtual photon exchange particle creates an attractive force

Question 18

what happens when two oppositely charged particles collide?

Answer 18

annihilate each other to create two photons

Question 19

what happens in pair production?

Answer 19

photon with energy greater than 1.022MeV create an electron and a positron

Question 20

what happens during beta minus decay?

Answer 20

neutron turns into a proton that emits an electron (beta minus particle) and anti electron neutrino

Question 21

what happens to proton number in beta minus decay?

Answer 21

+1

Question 22

what happens to nucleon number in beat plus/minus decay?

Answer 22

remains same

Question 23

what happens during beta plus decay?

Answer 23

proton turns into neutron that emits positron and electron neutrino

Question 24

what happens to proton number in beta plus decay?

Answer 24

-1

Question 25

what happens during electron capture?

Answer 25

proton captures electron to convert into neutron and emits an electron neutrino using a W+ boson

Question 26

what happens during electron-proton collision?

Answer 26

same as electron capture but using a W- boson

Question 27

what happens during strong interaction?

Answer 27

decay of charm-anticharm - annihilate to create 2 gluons that decay into hadrons proton-neutron interaction - strong interaction mediated by pion

Question 28

what is beta minus decay?

Answer 28

neutron -> proton + electron + anti electron neutrino

Question 29

what is beta plus decay?

Answer 29

proton -> neutron + positron + electron neutrino

Question 30

what is meant by unstable nuclei?

Answer 30

imbalance of forces within nucleus - too many or too few neutrons - nucleus too large

Question 31

what is radioactive decay?

Answer 31

process where an unstable nucleus emits radiation in the form of a particle or wave to become stable

Question 32

what are two characteristics of radioactive decay?

Answer 32

spontaneous and random

Question 33

what does spontaneous mean?

Answer 33

decay occurs without external influence

Question 34

what does a random process mean?

Answer 34

impossible to predict when a particular nucleus will decay

Question 35

what are three common ways to simulate random nature of radioactive decay?

Answer 35

- flipping coins - rolling dice - making popcorn

Question 36

what is an alpha particle composed of?

Answer 36

2 protons and 2 neutrons

Question 37

how penetrating is alpha radiation?

Answer 37

low penetrating - stopped by a few cm of air or by paper

Question 38

what is a beta minus particle?

Answer 38

a high-energy electron emitted from the nucleus

Question 39

what type of nuclei emit beta minus particles?

Answer 39

nuclei with too many neutrons

Question 40

what type of particles emit an alpha particle?

Answer 40

nuclei that is too large

Question 41

how penetrating is beta radiation?

Answer 41

moderately penetrating - few mm of aluminium foil

Question 42

what is gamma radiation?

Answer 42

high energy electromagnetic wave emitted by nuclei

Question 43

what type of nuclei emits gamma radiation?

Answer 43

nuclei with too much energy

Question 44

how penetrating is gamma?

Answer 44

highly penetrating - pass through several cm of lead

Question 45

what effect does radiation have on atoms they pass?

Answer 45

can knock out an electron and ionise atom

Question 46

what is decay constant?

Answer 46

probability per second that a given nucleus will decay

Question 47

what is half life?

Answer 47

time taken for initial number of nuclei in a radioactive sample to halve

Question 48

how to determine half life of an isotope experimentally?

Answer 48

measure count rate at regular intervals correct for background plot lnC against time find t₀.₅ from gradient

Question 49

what radioactive isotope if used in radioactive dating in organic material?

Answer 49

carbon-14

Question 50

how is carbon -14 produced in the atmosphere?

Answer 50

cosmic rays know out neutrons which collide with nitrogen-14 to produce carbon-14 and a proton

Question 51

why does carbon-14 decrease in a dead organism over time?

Answer 51

it is not being replaced after death so decays and is not replenished

Question 52

what is the limitation for carbon dating for very old samples?

Answer 52

too little C-14 in sample, so count rate similar to background count

Question 53

what does the theory of relativity propose?

Answer 53

mass can be converted to energy energy can be converted to mass

Question 54

why do nuclear fission and fusion release energy?

Answer 54

daughter nuclei have higher binding energy per nucleon than the reactants so mass difference released as energy

Question 55

what happens during annihilation of particle-antiparticle pair?

Answer 55

particles destroyed and mass converted to energy, producing two gamma ray photons

Question 56

what is pair production?

Answer 56

when a photon interacts with a nucleus or atom and its energy is used to create particle-antiparticle pair

Question 57

why is nucleus needed for pair production?

Answer 57

conserve energy and momentum

Question 58

what is minimum energy required from a photon during pair production?

Answer 58

at least total rest mass energy of particle and antiparticle

Question 59

what is binding energy?

Answer 59

energy required to break a nucleus into its individual nucleons

Question 60

what is mass defect in a nucleus?

Answer 60

difference of measured mass of nucleus and sum of individual nucleons

Question 61

why is mass of nucleus less than sum of nucleons?

Answer 61

mass is converted to energy and released when nucleus forms

Question 62

what does higher binding energy per nucleon indicate about nucleus?

Answer 62

nucleus is more stable

Question 63

what is nuclear fission?

Answer 63

splitting of large, unstable nucleus into smaller nuclei, releasing energy, neutrons, and gamma rays

Question 64

which elements are used for fuels in nuclear fission reactors?

Answer 64

isotopes of uranium and plutonium

Question 65

what happens to energy in nuclear fission reaction?

Answer 65

nuclear potential energy converted to kinetic energy of products

Question 66

what is chain reaction?

Answer 66

released neutrons induce more fission reactions, rapidly multiplying reactions

Question 67

what does a moderator in a nuclear fission reactor do?

Answer 67

slows down neutrons so they can efficiently cause further fission in fuel

Question 68

what do control rods do in a nuclear fission reactor?

Answer 68

absorb neutrons to prevent further fission

Question 69

what do coolants in a nuclear fission reactor do?

Answer 69

removes heat from the reactor core and transfers it to a heat exchanger for steam and electricity generation

Question 70

what is nuclear fusion?

Answer 70

process where small nuclides combine together to form a larger nuclei, releasing energy

Question 71

why do nuclei need high kinetic energy to fuse?

Answer 71

to overcome electrostatic repulsion between positively charged nuclei

Question 72

where does fusion occur naturally?

Answer 72

extremely hot and dense environments