Flashcards
AS AQA Physics Unit 2
Cards in this deck (11)
- 1Define a LeptonA lepton is a fundamental particle that doesn't interact through the strong force. They include electrons, muons and neutrinos.
- 2Define a HadronHadrons are particles that can interact through all 4 fundamental forces. They are split into baryons (made of 3 quarks) and mesons (a quark-anti quark pair)
- 3Sort the following particles into lepton, baryon or meson proton neutron electron neutrino muon pion kaonproton - baryon
neutron - baryon
electron - lepton
neutrino - lepton
muon - lepton
pion - meson
kaon - meson - 4What must be conserved in all reactions?Charge
baryon number
lepton number (electron, muon and tau)
Energy - 5What is not conserved in the weak interaction?Strangeness - because its strange. It is however, always conserved in strong interactions.
- 6What are lepton numbers?Numbers associated with any leptons, that must be conserved in all interactions.
+1 for leptons
-1 for anti leptons
0 for non leptons - 7What are the properties of Up, Down and Strange quarks?
- 8What is the quark combination for protons and neutrons?Proton = up, up, down (uud)
Neutron = up, down, down (udd) - 9What occurs during beta- decay?A neutron turns into a proton, emitting an electron and an anti electron neutrino.
One of the down quarks changes into a up quark.
udd --> uud
W- force carrier - 10What occurs during beta+ decay?A proton turns into a neutron, emitting a positron and an electron neutrino.
An up quark changes into a down quark
uud --> udd
W+ force carrier - 11Explain why some interactions are never observedBecause the reaction cannot happen, due to something not being conserved in the reaction