3.2 Particles and Radiation

Question 1

Alpha decay

Answer 1

decay by emitting a Helium nucleus to become more stable

Question 2

Annihilation

Answer 2

Particle and antiparticle meet, destroy eachother and emit radiation

Question 3

Antibaryon

Answer 3

Hadron consisting of three antiquarks

Question 4

Atomic number Z

Answer 4

Number of protons in an atom’s nucleus

Question 5

Baryon

Answer 5

Hadron consisting of three quarks. The proton is the only stable baryon

Question 6

Beta decay

Answer 6

when B- or B+ particles are emitted following decay of a neutron-rich or proton-rich nucleus

Question 7

Conservation rules

Answer 7

Rule that: Baryon No., Lepton No. Charge, Energy, Momentum. Always conserved in interactions

Question 8

When is strangeness conserved?

Answer 8

Strong interactions

Question 9

How are strange particles created?

Answer 9

Strong interactions

Question 10

How to strange particles decay?

Answer 10

Weak interactions

Question 11

de Broglie hypothesis

Answer 11

Matter particles have a wave-like nature

Question 12

de Broglie wavelength

Answer 12

Wavelength of a matter particle

Question 13

deexcitation

Answer 13

process by which atom loses energy by photon emission as electron moves to lower energy level - inner shell

Question 14

diffraction

Answer 14

spreading out of waves that pass through gap or near edge

Question 15

diffraction grating

Answer 15

plate with close parallel slits on it

Question 16

dispersion

Answer 16

splitting of beam of white light into colours by prism

Question 17

electromagnetic interaction

Answer 17

force or interaction between 2 charged objects

Question 18

electromagnetic wave

Answer 18

wavepacket or photon consisting of transverse electic and magnetic waves in phase and at right angle to eachother

Question 19

excitation

Answer 19

process in which atom absorbs energy without becoming ionised when electron moves from inner shell to higher energy level in outer shell

Question 20

energy

Answer 20

capacity to do work

Question 21

energy levels

Answer 21

discrete energy levels that electrons take in shells of atom

Question 22

gamma radiation

Answer 22

high energy photons emitted by unstable nuclei or produced in particle annihilations

Question 23

ground state

Answer 23

lowest energy state of an atom

Question 24

hadron

Answer 24

particles and anti that can interact through the strong interaction

Question 25

ion

Answer 25

charged atom

Question 26

ionisation

Answer 26

process of creating ions

Question 27

isotopes

Answer 27

atoms of the same element with a different number of neutrons and the same number of protons

Question 28

kaon

Answer 28

meson that has a strange quark and another quark

Question 29

lepton

Answer 29

particles that cannot interact through the strong interation

Question 30

matter waves

Answer 30

wave-like behaviour of particles

Question 31

meson

Answer 31

hadron made up of a quark and an anti quark

Question 32

muon

Answer 32

negatively charged lepton with a greater rest mass than the electron

Question 33

neutrino

Answer 33

uncharged lepton with a lower rest mass than the electron

Question 34

nucleon

Answer 34

N or P in nucleus

Question 35

nucleon number

Answer 35

number of P's or N's in the nucleus

Question 36

nuclide

Answer 36

type of nucleus with a particular number of P's and N's

Question 37

photoelectric effect

Answer 37

emission of electrons from metal surface when surface is hit with light with photons of frequency greater than threshold frequency

Question 38

photon

Answer 38

packet or 'quantum' of electromagnetic waves

Question 39

pion

Answer 39

meson with a u or d quark and antiquark

Question 40

pair production

Answer 40

gamma photon changed in a particle and corresponding antiparticle

Question 41

strong interaction

Answer 41

interaction between two hadrons

Question 42

strong nuclear force

Answer 42

attractive force between nucleons that holds the nucleons in the nucleus together

Question 43

Continuous Spectrum

Answer 43

continuous range of colours

Question 44

line emission spectrum

Answer 44

characteristic coloured lines due to discrete frequencies and corresponding wavelengths

Question 45

line absorption spectrum

Answer 45

dark vertical lines against continuous range of colours

Question 46

weak interaction

Answer 46

interaction between 2 leptons and between a hadron and a lepton

Question 47

weak nuclear force

Answer 47

force responsible for beta decay

Question 48

virtual photon

Answer 48

carrier of the electromagnetic force - no charge and zero rest mass

Question 49

W boson

Answer 49

carrier of the weak nuclear force - can have positive or negative charge and have non zero rest mass

Question 50

Antimatter

Answer 50

Antiparticles with same quantum values but opposite charge to corresponding particles

Question 51

threshold frequency

Answer 51

minimum frequency of light that will cause the photoelectric effect

Question 52

work function

Answer 52

minimum amount of energy needed by an electron to escape from a metal surface

Question 53

exchange particle for weak interaction

Answer 53

W- or W+ boson

Question 54

exchange particle for strong interaction

Answer 54

pion or gluon

Question 55

exchange particle for electromagnetic interaction

Answer 55

virtual photon

Question 56

exchange particle for gravitational interaction

Answer 56

graviton

Question 57

property of strange particles

Answer 57

made through strong interaction and decay through weak interaction

Question 58

when is strangeness conserved

Answer 58

conserved in strong interaction, not conserved through weak interaction

Question 59

significance of neurtino in beta decay

Answer 59

conserve momentum, conserve lepton number

Question 60

fluroescence

Answer 60

emission of visible photons after atoms deexcite

Question 61

excited state

Answer 61

an atom which is not in its ground state - lowest energy state

Question 62

nucleus

Answer 62

relatively small part of atom in centre, contains all of atom's positive charge, most of mass concentrated here

Question 63

electron capture

Answer 63

proton-rich nucleus captures inner shell electron, turns into neutron and releases electron neutrino - photon emitted when an electron fills the inner shell vacancy by moving to a lower energy shell