2 Particles and Radiation Flashcards
what is specific charge
the ratio of the charge of an ion to its mass
what is the nucleon number
the mass number (number of protons and neutrons)
what is the proton number
the atomic number (number of protons only)
what is an isotope
atoms with the same number of protons but different number of neutrons
what is alpha decay
typically for: large nuclei
emitted: two protons, two neutrons
what is beta minus decay
typically for: neutron rich nuclei
emitted: electron and antineutrino
what is beta plus decay
typically for: proton rich nuclei
emitted: positron and neutrino
what is gamma decay
typically for: after other decays - too much energy in nucleus
emitted: (EM radiation) photons
what is a neutrino
a subatomic particle with no electrical charge and a very small mass (could be zero)
why are there neutrinos
energy must be conserved
when do antiparticles arise
high energy collision experiments
interactions with cosmic rays
radioactive decay
what is an electron volt
eV - the kinetic energy of an electron, having been accelerated by 1V.
1eV = 1.6 x 10^-19J
Photon definition
‘under the photon theory of light: a photon is a discrete bundle/packet/quantum of electromagnetic or light energy.’
electromagnetic waves are emitted by a charged particle when it loses energy.
what is a photons behaviour
in motion: behaves like waves
in collisions: behaves like particles
what is annihilation
both particles collide and are destroyed and their mass is converted to energy in the form of 2 gamma photons.
photons are emitted in opposite directions to conserve momentum.
what is pair production
A photon interacts with an atom/nucleus to split into a pair (particle and antiparticle)
(The photon needs to have enough energy - must be above the total rest mass of both the particle and antiparticle pair.)
The particle and antiparticle pair will move in opposite directions to conserve momentum.
what are the four fundamental forces
electromagnetic
strong nuclear
gravitational
weak nuclear
what is the nature of the electromagnetic force
acts between all charged particles
what is the range for the electromagnetic force
infinite
what is the strength for the electromagnetic force
high
what is the exchange particle for the electromagnetic force
virtual photon
what is the exchange particle of the electromagnetic force
virtual photon
what is the nature of the strong nuclear force
acts between quarks
what is the range of the strong nuclear force
3 fm
[Attractive for separations above about 0.5 fm, but strongly repulsive for separations less than about 0.5 fm.]
