Particles and Radiation

State the mass and charge of the proton, neutron and electron

• Proton: $1.67\cdot10^{-27}$ kg, $1.6\cdot10^{-19}$ C

• Neutron: $1.67\cdot10^{-27}$ kg, 0 C

• Electron: $9.11\cdot10^{-31}$ kg, $-1.6\cdot10^{-19}$ C

Describe nuclide notation of AzX

A is the mass/nucleon number, Z is the atomic/proton number.

Define Isotope

Atoms of the same element (same number of protons) but a different number of neutrons

Define specific charge and its units

The amount of charge an object has per unit mass, charge per unit mass

($Ckg^{-1}$ )

How do some isotopes become more stable

The isotopes undergo radioactive decay

Define Carbon Dating

Looking at the amount of isotopes in a material to estimate its age

Define specific charge including the equation and units

• The amount of charge an object has per unit mass

• Specific charge = charge/mass

• Units = $Ckg^{-1}$

State what contributes to the charge and mass of a nucleus

• Only protons contribute to the charge of a nucleus

• Protons and neutrons contributes to the mass of a nucleus

State the four fundamental forces

Gravity, electromagnetism, strong nuclear force, weak nuclear force

State the properties of the strong nuclear force

• Repulsive less than 0.5fm

• Attractive between 0.5fm and 3fm

• No effect beyond 3fm

When does a nucleus become unstable

• Too much energy

• An imbalance between protons and neutrons contributes

• Too much mass

State what occurs in alpha decay

A nucleus emits an alpha particle consisting of 2 protons and 2 neutrons (Helium nucleus)

State what occurs in beta minus decay

A neutron turns into a proton through the weak nuclear force, releasing a beta particle (electron) and an electron antineutrino

State the force for beta decay

Weak nuclear force

State 2 things photons do not have

• Mass

• Electric Charge

Define annihilation

When a particle meets its anti-particle collide and release energy in the form of two photos moving in opposite directions to conserve momentum

Define rest energy

The energy stored in an objects mass

State the equation used for annihilation

$$2mc^2=2hf$$

Define pair production

When a photon turns into a particle and its antiparticle, if the photon has more than the minimum energy required for pair production, the excess becomes kinetic energy or enables the production of more massive particles

State the equation for pair production

$$hf=2mc^2$$

State how to convert from eV to Joules

multiply by $1.6×10^{-19}$

An anti-particle has the ___ but opposite ___ of the particle

• The same mass

• Opposite charge

State an equation relating and objects rest energy and mass

$$E=mc^2$$

State the differences between hadrons and leptons

• Hadrons can feel the strong nuclear force, leptons cannot

• Hadrons are made up of smaller particles called quarks, leptons are fundamental particles

State the 2 types of hadron

Baryons and mesons

Describe baryons and mesons and examples

Baryons

• Made up of 3 quarks

• The most stable baryon is the proton which all other baryons eventually decay into

• Examples: Protons, neutrons and sigmas

Mesons

• Made up of a quark and anti-quark

• Examples: Pions, Kaons

State which forces leptons and hadrons feel

The strong nuclear force, gravity and electromagnetic force if charged

State some examples of leptons

Electron, muon, electron neutrino, muon neutrino

State all quantum numbers

baryon number, lepton electron number, lepton muon number

State which leptons are stable

Electrons and neutrinos are stable

State all pion and kaon quark combinations

Pions (no strange quarks)

• $$\pi^{+}=u\overline{d}$$

• $$\pi^{-}=d\overline{u}$$

• $\pi^0=u\underline u$ and$d\underline d$

Kaons (contain strange quarks)

• $$K^{+}=u\overline{s}$$

• $$K^{-}=s\overline{u}$$

• $$K^0=d\overline{s}$$

• $$\overline{K^0}=s\overline{d}$$

State the quark compositions of protons and neutrons

• Proton = uud

• Neutron = udd

Why can quarks not exist on their own

Due to quark confinement → The energy required to pull them apart creates a new quark-antiquark pair (pair production)

State what must be conserved in particle interactions, include strangeness

• Charge

• Baryon Number

• Lepton electron number

• Lepton muon number

• Strangeness is sometimes conserved

  • Strangeness always conserved in strong interactions

  • Strangeness is not always conserved in a weak interaction (can change by +1, -1 or 0)

What causes strong and weak particle interaction

• Strong interaction is cause by the strong nuclear force (SNF)

  • Weak interaction is caused by the weak nuclear force (WNF)

State how to identify strong and weak particle interactions

Strong

• Only involves hadrons, no leptons

• Strangeness conserved

Weak

• Likely involves leptons

• Strangeness may not be conserved

• Often 1 particle decaying into 2 or 3

• If quark flavour changes/changes letter e.g. u→d

Describe all 4 fundamental forces in nature

• Gravity = Force acting between matter with mass, always attractive

• Electromagnetic force = acts between charged objects

• Strong nuclear force = holds atomic nuclei/protons and neutrons together

• Weak Nuclear Force = responsible for some radioactive decay and particle transformations

For each of electromagnetic, WNF, SNF and gravity, give their exchange particle and its properties and range

• Electromagnetic Force = Virtual Photon, 0 mass and 0 charge, infinite range

• Gravity = Graviton, 0 mass and 0 charge, infinite range

• Weak Nuclear Force = $W^+$and $W^-$ bosons, Has mass and charge, very short range

• Strong Nuclear Force = Pions (between nucleons) and gluons (between quarks), has charge and mass, very short range

State which particle interaction is given by the image

Beta Minus Decay

State which particle interaction is given by the image

Beta plus decay

State which particle interaction is given by the image

Electromagnetic/electrostatic repulsion (between electrons)

State which particle interaction is given by the image

Electron capture (←Think of it has +ve capturing -ve)

Electron-proton collision