Year 12 - Particles

Question 1

Annihilation

Answer 1

A corresponding particle and anti-particle (E.g. Electron and Positron) collide and annihilate each other. The mass is converted into energy in the form of two photons. Electric Charge, Baryon Number, Lepton Number, and Momentum are all conserved.

Question 2

Anti-Particle

Answer 2

Every particle has a corresponding Anti-Particle.

Similarity: Same (rest) mass or rest energy (1)
Difference: Opposite quantum states E.g. Charge, Baryon Number, Lepton Number (1)

Question 3

Baryon

Answer 3

A Hadron, composed of 3 Quarks. Note: Anti-Baryon would be 3 Anti-quarks.

Question 4

Baryon Number

Answer 4

A quantum number identifying that a particle is a Baryon E.g. B=+1. Baryon Number is always conserved during an interaction.

Question 5

Beta Minus Decay

Answer 5

A (Free) Neutron (udd) changes into a Proton (uud) via the weak interaction (W- Boson) and emits a Beta Minus Particle and an Anti-neutrino.

Question 6

Beta Plus Decay

Answer 6

A (Free) Proton (uud) changes into a Neutron (udd) via the weak interaction (W+ Boson)and emits a Beta Plus Particle (Positron) and a Neutrino.

Question 7

Charge

Answer 7

Charge, Q, isa physical quantity, which can be either positive or negative. A charged particle will experience an EM Force.

Question 8

Distribution of kinetic energies of β- particles

Answer 8

Existence of Neutrino. Beta particles have a range of (kinetic) energies. There is a fixed/maximum/total amount of energy (released) so there must be another particle that carries the energy differences/missing energy away.

Question 9

Down Quark

Answer 9

1) Charge: -1/3
2) Baryon Number: +1/3
3) Strangeness Number: 0

Question 10

Electron

Answer 10

A fundamental particle with a charge of -1e and Electron Lepton Number of +1.

Question 11

Electron Capture

Answer 11

(Inner) orbiting electron [or electron surrounding the nucleus] captured by a proton (in the nucleus) converted into a neutron via the weak interaction (W+ Boson).

Question 12

Electron Diffraction

Answer 12

The diffraction of electrons as they pass through a gap similar to the magnitude of their de Broglie wavelength. It is evidence of the wave-like properties of particles.

Question 13

EM Force

Answer 13

The force of attraction or repulsion between two particles/bodies that have charge. The exchange particle for the EM Force is the Virtual Photon.

Question 14

Exchange Particle

Answer 14

Theexchange particleis also known as a virtualparticle. It only exists for a very brief moment and its only role is to carry the force between theparticles. Exchange particles transfer Momentum.

Question 15

Fundamental Particle

Answer 15

A particle that has no subatomic constituent parts.

Question 16

Gauge Boson

Answer 16

Force carrying particles that carry the fundamental forces.

Question 17

Gravitational Force

Answer 17

The force of attraction between two particles/bodies that have mass. The exchange particle for Gravity is the Graviton.

Question 18

Hadron

Answer 18

Experience the Strong Force and composed of Quarks.

Question 19

Ion

Answer 19

An atom that has either gained or lost electrons.

Question 20

Isotope

Answer 20

Atoms with the same number of Protons and a different number of Neutrons.

Question 21

Lepton

Answer 21

Leptons are fundamental particles which interact with all the fundamental forces except for the strong nuclear force.

Question 22

Lepton Number

Answer 22

A quantum number identifying that a particle is a Lepton E.g. L=+1. Lepton Number is always conserved. Lepton number can additionally be divided into sub-categories, to show where it is an Electron or Muon.

Question 23

Mass

Answer 23

Mass, m, isa physical quantity. A particle or body with mass will experience a Gravitational Force.

Question 24

Meson

Answer 24

Hadron, composed of a Quark, Anti-quark Pair.

Question 25

Muon

Answer 25

Leptons which are heavier versions of the Electron. They decay into Electrons. A fundamental particle with a charge of -1e and Muon Lepton Number of +1

Question 26

Negative Kaon

Answer 26

1) Composition: Strange, Anti-Up 2) Charge: -1 3) Baryon Number: 0 4) Strangeness: -1

Question 27

Negative Pion

Answer 27

1) Composition: Down, Anti-Up 2) Charge: -1 3) Baryon Number: 0

Question 28

Neutral Kaon

Answer 28

1) Composition: Down, Anti-Strange 2) Charge: 0 3) Baryon Number: 0 4) Strangeness: +1

Question 29

Neutral Pion

Answer 29

1) Composition: Up, Anti-up or Down, Anti-Down 2) Charge: 0 3) Baryon Number: 0

Question 30

Neutrino

Answer 30

A subatomic particle whose existence was hypothesised to maintain the conservation of energy/mass in beta decay. They have negligible mass. They also have different flavours E.g. Electron Neutrino, Muon Neutrino.

Question 31

Neutron

Answer 31

1) Composition: udd 2) Charge: 0 3) Baryon Number: +1

Question 32

Nucleon

Answer 32

The collective term for protons and neutrons E.g. Sub-atomic particles that are in the nucleus.

Question 33

Nucleon Number (A)

Answer 33

The number of nucleons in the nucleus E.g. Protons + Neutrons.

Question 34

Pair Production

Answer 34

A photon interacts with orbital electron/nucleus in order to conserve momentum, energy of photon used to create corresponding particle anti-particle pair (E.g. Electron and Positron). Charge, Baryon Number, Lepton Number, and Momentum are all conserved.

Question 35

Particulate nature of electrons

Answer 35

Charged particle moving in a Magnetic Field or Particle Collisions.

Question 36

Particulate nature of light

Answer 36

Photoelectric effect.

Question 37

Positive Kaon

Answer 37

1) Composition: Up, Anti-Strange 2) Charge: +1 3) Baryon Number: 0 4) Strangeness: +1

Question 38

Positive Pion

Answer 38

1) Composition: Up, Anti-Down 2) Charge: +1 3) Baryon Number: 0

Question 39

Positron

Answer 39

Positively charged particle that is the antiparticle of an electron. The Electron is the only particle to have an anti-particle with its own name.

Question 40

Proton

Answer 40

1) Composition: uud 2) Charge: +1 3) Baryon Number: +1

Question 41

Proton Number (Z)

Answer 41

The number of protons in the nucleus of an Atom. E.g. A Lithium nucleus contains 3 protons.

Question 42

Quarks

Answer 42

Fundamental Particle that can combine to form Baryons and Mesons.

Question 43

Specific Charge

Answer 43

Charge to Mass Ratio (Ckg-1)

Question 44

Strange Quark

Answer 44

1) Charge: -1/3 2) Baryon Number: +1/3 3) Strangeness Number: -1

Question 45

Strangeness

Answer 45

Strangeness occurs if a particle has a strange quark. Strangeness is conserved in strong interactions; but not in weak interactions.

Question 46

Strong Nuclear Force (Interaction)

Answer 46

The force between Quarks/Hadrons. It is responsible for keeping nucleus together. The strong force only acts over a range of 3fm. Between the distance of 3fm and 0.5fm separation the force is attractive. Below 0.5fm separation the force is repulsive.

Question 47

Up Quark

Answer 47

1) Charge: +2/3 2) Baryon Number: +1/3 3) Strangeness Number: 0

Question 48

Wave nature of electrons

Answer 48

Electron diffraction.

Question 49

Wave nature of light

Answer 49

Interference e.g. Single/Double Slit Experiment

Question 50

Weak Interaction

Answer 50

The weak interaction is responsible for the decay of atoms; The exchange particles that carry this force are the W– and W+ Bosons.