nuclear physics and particle physics Flashcards
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Explain why the activity of a radioactive material is a major factor when considering the safety precautions in the disposal of nuclear waste
Short half life means a high initial activity
Precautions will be needed for the initial period of disposal
A material with a long half life will stay radioactive for a long time, so needs long term disposal
what’s required for nuclear fusion
To fuse, nuclei must be close enough for the strong nuclear force to attract them. However, they naturally repel each other due to their positive charges. High temperature and velocity give them enough energy to overcome this repulsion and collide.
What are protons and neutrons classified as?
Protons and neutrons are classified as baryons, which are a type of hadron made of three quarks.
What are mesons?
Hadrons made up of a quark and an antiquark are called mesons.
What is the composition of a proton?
A proton is composed of two up quarks and one down quark (uud).
What is the composition of a neutron?
A neutron is composed of one up quark and two down quarks (udd).
What can the weak nuclear force do?
The weak nuclear force can change the type of quark.
What happens in beta-minus decay?
In beta-minus decay, a neutron is changed into a proton, an electron, and an antineutrino.
What happens in beta-plus decay?
In beta-plus decay, a proton changes into a neutron, a positron, and a neutrino.
What is always conserved during decay?
Charge is always conserved.
What binds individual quarks together?
Individual quarks are bound together by the strong nuclear force.
What causes radioactive decay?
Radioactive decay occurs when a nucleus is unstable and breaks down to become more stable.
What are some reasons for a nucleus to be unstable?
A nucleus may be unstable due to too many neutrons, too many nucleons, too few neutrons, or too much energy.
What is the nature of radioactive decay?
Radioactive decay is spontaneous and random.
How can the presence of radiation be detected?
A cloud chamber can be used to detect the presence of radiation.
What is alpha radiation?
Alpha radiation consists of a helium nucleus, which has 2 protons and 2 neutrons.
What is beta radiation?
Beta radiation consists of fast-moving electrons.
What is gamma radiation?
Gamma radiation consists of high-energy photons of electromagnetic radiation.
What is the parent nucleus?
The nucleus before decay is called the parent nucleus.
What is the daughter nucleus?
The nucleus after decay is called the daughter nucleus.
What is the half-life of an isotope?
The half-life of an isotope is the average time it takes for the number of radioactive nuclei to halve.
How is the activity of a source measured?
The activity of a source is measured in Bq and depends on the half-life of the isotope and the number of undecayed nuclei present.
What is the decay constant?
The decay constant is the probability of decay of an individual nucleus per unit time.
What is carbon dating?
Carbon dating determines the age of relics by comparing the ratio of carbon-14 to carbon-12 nuclei.
What is alpha decay?
Alpha decay releases a helium nucleus, reducing the mass number by 4 and the atomic number by 2.
What is beta-minus decay?
In beta-minus decay, a neutron turns into a proton and an electron, releasing an anti-electron neutrino.
What is beta-plus decay?
In beta-plus decay, a proton turns into a neutron and a positron, releasing an electron neutrino.
What is Einstein’s mass-energy equation?
Einstein’s mass-energy equation states that mass is a form of energy and energy has mass.
What is binding energy?
Binding energy is the minimum energy required to completely separate a nucleus into its constituent protons and neutrons.
What is nuclear fission?
Nuclear fission uses uranium-235, which absorbs a neutron and splits into smaller nuclei, releasing energy.
What is a chain reaction in nuclear fission?
A chain reaction occurs when each fission event produces more neutrons, leading to exponential growth.
What are control rods in a fission reactor?
Control rods are made of materials that absorb neutrons to regulate the fission reaction.
