Particle Physics Flashcards
Lead box with slit (experiment)
- To ensure a single path for alpha particles
- Alpha particles are absorbed by lead
Vacuum (experiment)
- To ensure sufficient alpha particles reach the foil
- Because alpha particles would collide with air molecules
Zinc sulphide screen
- Scintillates (emits light) when the alpha particles hit it
- to detect the particles and their direction
Most of the alpha particles were undeflected (analysis)
Most did not get near enough to any matter or charge to be affected
Most of the alpha particles were deflected (conclusion)
The atom is mostly empty space
A few particles were deflected (analysis)
Only a few particles came close enough to charge to be deflected
A few particles were deflected (conclusion)
The atom contains a small region of highly concentrated charge
A very small proportion of alpha particles were deflected through more than 90 (analysis)
An area of the atom must have mass much greater than the alpha particle mass to cause this deflection
A very small proportion of alpha particles were deflected through more than 90 (conclusion)
Most of the mass of the atom is concentrated in a very small space relative to the size of the atom
Quark (gen 1)
- up (+2/3)
- down (+2/3)
Quark (gen 2)
- Charm (+2/3)
- Strange (-1/3)
Quark (gen 3)
- Top (+2/3)
- Bottom (-1/3)
Leptons (gen 1)
- Electron (-1)
- Electron neutrino (0)
Leptons (gen 2)
- Muon (-1)
- Muon neutrino (0)
Leptons (gen 3)
- tau (-1)
- tau neutrino (0)
Quarks
A quark is a type of fundamental particle. Quarks combine to form composite particles called hadrons,
the most stable of which are protons and neutrons.
Lepton
A lepton is an fundamental particle that does not undergo strong interactions. It always exists alone
Antimatter
material composed of antiparticles, which have the same mass as particles of ordinary matter but opposite charges, as well as other particle properties such as lepton and baryon numbers and quantum spin
Describe what happens when matter and antimatter meet? (2 Marks)
- Annihilate each other
- Gamma rays (high energy photons) given off
Explain why it is difficult to store antimatter? (2 marks)
- When it touches matter (the sides of the container)
- Annihilate each other
Hadrons
- BARYONS (proton and neutron)
- MESONS (pion and kaon)
Baryon
Is a composite subatomic particle made up of three quarks, bound together by the strong interactions
Mesons
subatomic particles composed of one quark and one antiquark, bound together by the strong interaction
What needs to be conserved during nuclear reactions:
- Momentum
- Charge
- Baryon number
- Lepton number
Baryon number of baryon(proton, neutron, sigma)
+1
Baryon number of baryon antiparticle (antiproton)
-1
Baryon number of mesons (pion, kaon)
0
Baryon number of leptons (electron, positron)
0
Lepton numbers:
- Lepton +1
- Antilepton -1
- Other particle 0