Particles and Radiation Flashcards
(52 cards)
what is the charge and mass of a proton?
+1.6x10^-19 and 1.67x10^-27
what is the charge and mass of a neutron?
0 and 1.67x10^-27
what is the charge and mass of an electron?
-1.6x10^-19 and 9.11x10^-31
what is specific charge and how do you calculate it?
it is the ratio of an atoms charge to its mass specific charge = charge/mass
What is an isotope?
Atoms of the same element that have different numbers of neutrons
what does electromagnetic force do in the nucleus?
causes the positively charged protons in the nucleus to repel each other
what does gravitational force do in the nucleus?
causes all the nucleons in the nucleus to attract each other due to their mass
what force stops the electromagnetic force tearing the nucleus apart?
strong nuclear force
what is the range of strong nuclear force?
it can hold nucleons together when they are separated by up to about 3fm(x10^-15)
why is the strong nuclear force repulsive up to about 0.5fm(x10^-15)?
otherwise there would be nothing to stop it crushing the nucleons to a point
what can you say about the size of the strong nuclear force whether it’s p-p, n-n or n-p?
it is the same as it works equally between all nucleons
how were neutrinos discovered?
it was observed that energy after beta decay was less than before, conservation of energy means a particle is responsible for making up the rest of the energy and momentum - the neutrino
what are the 7 types of EM radiation and how do wavelength and frequency change along the spectrum?
radiowaves, microwaves, infra-red, visible light, ultra-violet, x-rays, gamma rays. frequency increases down the spectrum, wavelength decreases
what is the relationship between the frequency and energy of a wave?
the higher the frequency the greater its energy
what is a photon and the equation of calculating their energy?
they are discrete waves (packets which carry energy) energy = (h x C)/wavelength
what is an anti-particle?
a particle which has the same mass and rest energy but opposite charge to it’s other in the particle - antiparticle pair
what can you assume about the rest energy of a neutrino and why?
that it is 0 because their mass is so small
what is pair production and what is required for it to happen?
when energy is converted into mass you get equal amounts of matter and anti-matter (this is pair production), it only happens if there is enough energy to produce the masses of the particles
in pair production why would the two particles produced curve away from each other in an applied magnetic field?
because they have opposite charges
what is the minimum energy needed for pair production?
it is the total rest energy of the particles produced (Emin=2E0)
what happens when a practice meets its antiparticle?
the annihilate, all mass is converted back to energy in the form of two gamma ray photons (2Ephotons=2E0)
how is annihilation used in industry?
in PET scanners - positron emitting isotope put it into the bloodstream and gamma rays produced are detected
what are hadrons and what are the 2 types?
they are non-fundamental particles which can feel the strong nuclear force. they are split into baryons and mesons
what are baryons (with examples) and what do they all decay into and why?
all baryons are made up of three quarks, for example protons and neutrons. all baryons eventually decay into protons because a free proton is not unstable
