Particles and Radiation Flashcards
What is Specific Charge?
Charge divided by mass
What force acts between nucleons at short distances?
Strong Nuclear Force
At what distance is the strong nuclear force repulsive?
<0.5fm
At what range in distances is the strong nuclear force attractive?
0.5fm-3fm
Why is the strong nuclear force needed?
- To prevent the nucleus from collapsing in on itself
- To overcome elctrostatic repulsion between protons
What is beta minus decay?
When a neutron turns into a proton.
Or…
When a down quark turns into an up quark.
What is beta plus decay?
When a proton turns into a neutron
What is alpha decay?
When an alpha particle ( helium nucleus ) is emitted.
Define annihilation.
A particle and its corresponding antiparticle colliding, releasing two photons travelling in opposite directiosn to conserve momentum
Define Pair production.
A photon is converted into a particle and antiparticle pair
State the four fundamental forces.
Gravity
Electromagnetic force
Weak nuclear force
Strong nuclear force
Define electron capture.
A proton capture an inner shell elctron turning them into a neutron and an electron neutrino. A W+ boson is exchanged.
Define a proton-electron collision.
A proton and electron collide and exchange a W- boson. These turn into a neutron and electron neutrino.
What are leptons?
Fundamental particles.
What is a fundamental particle?
A particle that cannot be broken down into smaller components.
What are baryons made of?
3 quarks
What are antibaryons made of?
3 antiquarks
What is the only stable baryon?
The proton
What interaction do leptons interact by?
Weak nuclear force ( weak interaction)
How do hadrons interact?
Strong nuclear force
How can hadrons be further classified?
Baryons and mesons
What are mesons?
A quark and antiquark
State 3 examples of leptons.
Electron
Neutrino
Muon
What is the stable lepton?
Electron
What is conserved in particle interactions?
Momentum, energy, quantum numbers, charge, (and sometimes strangeness)
Define work function.
The minimum amount of energy required to remove an electron from a metal’s surface.
What is the threshold frequency?
The minimum frequency of photons required for photoelectrons to be emitted from a metal plate’s surface via the photoelectric effect.
What is the photoelectric effect?
The emission of electrons off a metal’s surface due to the absorption of electromagnetic radiation.
Define stopping potential.
The minimum potential difference required to stop the highest kinetic energy electrons from being emitted from a metal plate.
