Particles Flashcards
What is the formula for specific charge ?
Charge/Mass
How do you calculate the specific charge of a nucleus ?
1.6x10^-19 x number of protons / nucleon number x 1.67x10^-27
When calculating specific charge of a ion what must you include ?
charge of the ion is the overall charge e.g. 2-
so use 2 x e
for mass the ion the mass of the electrons are included
What is a alpha particle ?
2protons and 2 neutrons
What is beta- and beta+ particles /
electron and positron respectively.
What is the third product of beta- decay ?
anti electron neutrino.
What is the the third product of beta+ decay ?
electron neutrino
What is the formula for energy mass equivalency and what does it mean ?
E = mc ^2
energy and mass are interchangeable
How do you convert between j and eV ?
multiply or divide by 1.6x10^-19
(joules is always a very small number but eV are large)
What is a antiparticle ?
A particle with same mass but opposite charge as its corresponding particle.
Describe annihilation.
A particle anti particle pair collide to produce 2 high energy photons where sum of energy of photons is equal to mass energy of particle antiparticle pair.
Why is p conserved in annihilation ?
momentum of 2 particles are equal and opposite and afterwards the 2 photons have momentum that are equal and opposite.
Describe pair production.
A high energy photon ceases to exist to become a particle antiparticle pair where photon energy is equal to mass energy of particle antiparticle pair.
How is p conserved in pair production ?
The vertical components of the particle antiparticle pair cancel each other and their horizontal components sum to equal momentum of photon.
What are the 4 fundamental forces and what do they do ?
Strong - holds nucleons in the nucleus together
Weak - acts on quarks and leptons to cause particles to decay
Electromagnetic - acts on charged particles to hold atoms and molecules together
Gravity - negligible on small scales not necessary in this topic
What is a proton made of ?
U U D
What is a neutron made of ?
D D U
What are leptons ?
interaction particles involved in weak interactions (decay)
What are hadrons ?
Particles made of quarks and are involved in strong interactions.
What are the 2 types of hadrons and give a example of both.
Mesons K+
Baryon proton
What are the particles associated with the fundamental forces ?
strong - gluon
EM - photon
Weak - Z boson (has mass) W boson ( has mass and charge)
What are the conserved quantities in particle physics ?
Charge
baryon number
Lepton number
Strangeness ( only in strong interactions otherwise can charge by 1)
What are the baryon numbers for baryons ?
baryons +1
antibaryons -1
What are the lepton numbers for all leptons ?
leptons +1
antileptons -1
What distinguishes K mesons wit pi mesons /
K mesons have a strangeness ( k+ and 0 have s=+1 and K- have s=-1)
