particles and radiation

specific charge

charge to mass ratio

isotope

atoms with the same number of protons and different numbers of neutrons

carbon dating

calculates the percentage of carbon 14 in an object to calculate an approximate age

strong nuclear force

keeps nuclei stable by counteracting the electromagnetic force between protons in the nucleus

only attractive between 3fm and 0.5fm

unstable nuclei

nuclei with too many protons neutrons or both

alpha decay

occurs in large nuclei

proton number decreases by 2 nucleon number decreases by 4

beta minus decay

occurs in neutron rich nuclei

proton number increases by 1 nucleon number stays the same

why where neutrinos hypothesised

observations of particle energy levels before and after beta minus decay showed energy was not conserve

electron anti particle

positron

photon

packet of electromagnetic radiation which transfer energy and have no mass

energy of photons 

directly proportional to the frequency of electromagnetic radiation

plancks constant

6.63x10^-34

annihilation

when a particle and corresponding antiparticle collide

mass of particles turn to energy which is released as two photons moving in opposite directions to conserve momentum

application of annihilation

PET scanner which produces 3d images of the inside of the body to help diagnoses

pair production

where a photon is converted into equal amounts of matter and antimatter

only happens when photon has energy greater than total rest energy of both particles

excess energy converts to particles kinetic energy

what are the 4 fundamental forces

strong electromagnetic weak gravity

exchange particles

cause forces between particles

carry energy and momentum between particles experiencing the force

strong force exchange particle

gluon

what do gluons act on

hadrons

weak exchange particle

w boson

what do w bosons act on

all particles

electromagnetic exchange particle

virtual photon

what do virtual photons act on

charged particles

what does the weak nuclear force do

beta decay electron capture and electron proton collisions

specific charge units

C/kg

nucleon

proton or neutron particles found in the nucleus

beta minus decay

neutron turns into proton

electron and anti electron neutrino

structure of alpha particle

two protons and two neutrons

helium nucleus

antiparticle

for every particle there is an antiparticle with the same rest energy and mass but all other properties opposite of its respective particle

electron capture or electron proton collision

proton plus electron to neutron plus electron neutrino

beta plus decay

proton to neutron plus positron plus electron neutrino

beta minus decay

neutron to proton plus electron plus anti electron neutrino

lepton

fundamental particles which dont experience the strong force

hadron

made of quarks and experience the strong force

baryon

made of three quarks

meson

quark antiquark pair

baryon number

always conserved

which is the only stable baryon

proton

lepton number

always conserved split into electron and muon lepton number

what does a muon decay to

electron

strange particles

produced by the strong interaction and decay by the weak interaction

strangeness

shows that strange particles must be created in pairs

what do kaons decay to

pions

proton quark combination

up up down

neutron quark combination

up down down

properties that must be conserved

energy momentum charge baryon number electron lepton number and muon electron number

what interaction is strangeness conserved in

strong

photoelectric effect

where photoelectrons are emitted from the surface of a metal after light above a certain frequency is shone on it

threshold frequency

frequency at which the photoelectric effect begins

how many photons do each electron absorb

one

what happens if light intensity is increased in the photoelectric effect

more photonelectrons are emitted per second if frequency is above the threshold

work function

minimum energy required for electrons to be emitted from a metals surface

stopping potential

potential difference needed to be applied to stop the emission of photoelectron

where can electrons exist in atoms

discrete energy levels

excitation

when electrons move up an energy level due to collisions with free electrons

ionisation

when free electrons collide with an atom with enough energy to remove the electron from the atom entirely