P7: Radioactivity Flashcards
What is the mass number of an element?
- The top number
- The proton + neutron number
What is the atomic number of an element?
- The bottom number
- The proton number
True or False: an alpha particle is the same as a Hydrogen nucleus?
False: it is the same as a Helium nucleus
What are Gamma rays?
Short wavelength electromagnetic radiation emitted by the nucleus of an atom
What is a Beta particle?
A high-energy electron
What is meant by the ionising power of radiation?
A measure of how easily ionising radiation can move electrons from atoms, leaving positive ions behind
Which has the highest/lowest ionising power?
- Highest = Alpha radiation
- Lowest = Gamma rays
True or False: irradiation of an object causes it to become radioactive?
False: the object is exposed to nuclear radiation but doesn’t become radioactive
Define radioactive contamination
The unwanted presence of radioactive atoms in/on object/body. It is hazardous because it decays in this position.
Define Half-Life
The time taken for the number of unstable nuclei in a sample of an isotope to halve
What is meant by the activity of a radioactive source?
The rate at which a source of unstable nuclei decays.
Give an example of natural and man-made sources of background radiation
Natural: - air - food - rocks - cosmic rays Man-made: - fallout from nuclear explosions - nuclear waste
True of False: Fusion is the splitting of radioactive atoms?
False:
- Fission is splitting
- Fusion is joining
Fill in the gaps: a nuclear reactor uses a ___ ___ ___ to maximise the energy released from the fuel
controlled chain reaction
Does fission use neutrons to split atoms?
Yes, from each split more neutrons are produced to continue the chain reaction.
