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27 Cards in this Set
- Front
- Back
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WHo published periodic table
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Russian Chemist Dmitri Ivanovich Mendeleev in 1860s
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Who discovered the positively charged atomic nucleus contained vitually all mass of an atom
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Rutherford, Geiger and Marsden
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Whats an elementary particles
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not a combination of other particles
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Lepton
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low mass elementary particle Electron, neutrino |
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Quark
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Elementary particle not found in isolation, combines to form hadrons and baryons Up, down |
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Hadron
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Higgh mass particle consisting of quarks and anti-quarks |
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Baryon
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Hadron composed of 3 quarks proton neutron |
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Antibaryon
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Hadron composed of three anti-quarks Antoproton |
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Meson
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Hadron composed of a quark and antiquark Pion |
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UNit for energy in particle physicts
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electron volts (ev)
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Learn standard model particles charge lepton number, baryin number, symbol |
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Antimatter
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All quarks and leptons have equivalent antiparticles Same properties except the charge is equal and opposite |
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Annihilation
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When a particle and antiparticle interact with each other they annihilate - they disappear and their mass energy manifests itself as two photos of electromagnetic radiation
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Energy converted equation
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E=MC^2
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Energy of photon
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Total mass energy+KE energy
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Elementary charge (an electron)
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1.602x10-19
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Rams horn effect
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when an electron positron pair are created a high energy photon enters from the top and interacts with a hydrogen atom, ejecting a high energy electron, creating low energy electron-positron pare and a second photon which continues A magnetic field at right angles to the page makes the charged particles travel in curves and the oppoisite charges of the positron-electron pair creates the RAMS HORN |
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What are neutrinos
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Particles of very low mass which only interacts via weak force need to come within 10-18 so interactions hardly ever happen |
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Quark combination for proton
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uud
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for neutron
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udd
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what forces affect particles
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gravitational electromagnetic strong weak |
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Gravitational
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affects all matter infinite range very weak - negligible for subatomic particles |
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Weak force
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affects all leptons, all quarks, all hadrons, all particles range = 10-18 m Only significant when e-m and strong inteactions do not operate neutral leptons involved may be a CHANGE IN QUARK FLAVOUR Very unlikely when two particles collide |
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electromagnetic
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All charged particle infinite range Also by neutral hadrons because quarks have charge One or more photons emitted no change in quark flavour |
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Strong Force
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All quarks range = 10-15 Binds quarks together in hadrons Bind protons and neutrons in the nucleus Very likely when particles collide No change in quark flavour U and D must be conserved |
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Decay lifetimes for different forces
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STRONG = 10-24s ELECTROMAGNETIC = 10-12s WEAK = 15 mins |
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Conservation Laws
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Lepton number Baryon Number Charge number Quark Flavour |
