Nuclear Flashcards
(51 cards)
What do the top and bottom number of an element represent?
Top - nucleon number A
Bottom - proton number Z
Define an isotope
Atoms of the same element with the same number of protons but a different number of neutrons in the nucleus.
What is conserved in a nuclear reaction?
The nucleon number A and the charge (so proton number Z)
What is the equation used to find the distance from the centre of the alpha particle to the centre of the gold nucleus at closest approach?
1/2 mv^2 = Qq / 4πε0r
Loss of KE = gain in electrostatic PE
What is true about the density of all nuclei?
It is constant independent of the nucleon number.
What type of particles experience the strong nuclear force and which do not?
Hadrons do
Leptons do not
What are the fundamental particles?
Leptons: Electron, positron, neutrino, anti-neutrino.
What is true about fundamental particles?
They have no sub-structure.
What forces do both leptons and hadrons experience?
Gravitational, electromagnetic, weak nuclear.
What are the baryons?
Proton, antiproton, neutron, antineutron.
What is true about meson’s quarks?
They have a quark-antiquark pair.
Define a lepton
A fundamental particle with no sub-structure. They do not interact via the strong force.
What is true about a particle and its corresponding antiparticle?
They have the same mass and opposite charge (if charged particles)
What is true about the lepton or baryon number of an anti-particle and a particle?
The particle has a lepton/baryon number of 1. The antiparticle has a lepton/baryon number of -1.
Define a hadron
Not a fundamental particle, they have a sub-structure of quarks. They do interact via the strong force.
Define beta minus decay
When a nuclei has too many neutrons, a neutron decays into a proton plus an electron and anti-neutrino.
Define beta plus decay
When a nuclei has too many protons, a proton decays into a neutron plus a positron and a neutrino.
Define annihilation
When a particle meets its anti-particle they annihilate. They are both destroyed and their mass is converted into photon energy.
Define binding energy
The energy required to split a nucleus completely into separate protons and neutrons.
Define mass defect
(Mass of protons + mass of neutrons) - mass of nucleus
What conditions are needed for fusion?
Very high temperature so very high KE to overcome the force of electrostatic repulsion and very high density to give a high probability of head-on collisions.
Define spontaneous fission
A large nucleus splits into 2 smaller nuclei plus several neutrons and releases energy.
Define induced fission
A large nucleus absorbs a neutron and splits into 2 smaller nuclei plus several neutrons and releases energy.
Define nuclear fusion
2 small nuclei fuse to form a larger nucleus and releases energy.
