Matter and Radiation - 1 Flashcards
What does the word nucleon include?
protons and neutrons - nucleus
What is the charge of the nucleus
positive depending on the number of protons
what type of microscope do you need to see atoms?
electron microscope
What did Rutherfords alpha scattering experiment show?
positively charged nucleus and elections surrounding nucleus.
What holds electrons in the atom?
electrostatic force
What two sub atomic particles have similar masses?
protons and neutrons
what is an isotope?
an atom of an element with the same number of protons but a different number of neutrons.
what is the nucleon number?
number of protons and neutrons
what is the mass number?
same as the nucleon number
what is specific charge?
charge / mass
what holds stable nuclei together in a stable nucleus?
strong nuclear force
what does the strong nuclear force overcome?
electrostatic force between protons
what is the range of the strong nuclear force when its attractive?
0.5 - 4 fm ( 1 fm = 1x^-15 m)
what range is the strong nuclear force repulsive?
0-0.5 fm
what is alpha radiation
2 protons 2 neutrons
what type of radiation is detected in PET scanners?
gamma radiation
what happens when a corresponding particle and antiparticle collide?
they anhililate
what is an antiparticle?
a particle with equal and opposite charge and equal rest mass
what’s the difference between pair production and annihilation?
pair production is where photons create a particle and antiparticle, while annihilation is where a particle and corresponding antiparticle collide and create two photons.
what are the products of annihilation?
radiation energy - two photons
what’s the minimum energy of a photon in pair production?
hf min = E0
what’s the minimum energy of a photon in a pair production?
hf min = 2E0
what did Feynman say was the reason for electromagnetic particles?
virtual photons (y)
what is the virtual photon represented by in a Feynman diagram?
a wave
describe the weak nuclear reaction with a Feynman diagram
neutrino + neutron = proton + beta minus including w- boson
antineutrino +neutron = proton + beta plus. including w+ boson
describe beta - decay with a Feynman diagram?
neutron = antineutrino + w- boson + beta minus + proton
describe beta + decay with a Feynman diagram?
proton = neutrino + neutron + beta+ + w+ boson
describe electron capture on a Feynman diagram?
proton + e- = neutron + neutrino
name two force carriers
photons and w bosons
describe the interaction that is responsible for keeping protons and neutrons together in a stable nucleus
strong interaction repels 0-0.5fm attracts 0.5-3 fm keeps nuclei at an equilibrium distance from each other short distance and acts on hadrons
how is baryon number conserved in alpha decay?
the number of protons and neutrons stays the same, therefore baryon number is conserved
how is baryon number conserved in beta decay?
a neutron turns into a proton and so baryon number stays the same, and an electron has a baryon number pf 0 and so no change
if an atom gains an electron what charge does it have?
negative
if an atom loses an electron what charge does it have
positive
to create a new element what must happen?
the atom most gain or lose a proton
at what range does the electrostatic force work?
its long range and follows the inverse square law
how do you identify a strange particle?
it has a strange quark + usually decays via the weak interaction
