Atoms and NUclear Radiation Flashcards
Why do unstable nuclei give out radiation?
- Unstable nuclei undergo decay to become more stable.
* As they release radiation they become more stable.
What is the name given to the process in which an unstable nucleus gives out radiation to become more stable?
Radioactive decay.
Define the activity of an unstable nucleus.
Activity to the rate of decay of a source of unstable nuclei.
What is the unit if radioactive activity?
Becquerel (Bq)
What is count-rate
The number of radioactive decays per second of a radioactive source.
Give an example of a detector that may be used to measure count rate.
Geiger-Muller tube
State four types of nuclear radiation
- Alpha particles - 2 protons and 2 nuclei (helium nucleus)
- Beta particles - Fast moving Electron
- Gammer rayes
- Neutrons
What is the range of an alpha particle through air?
Few centimeters (2-10cm)
What can stop a beta particle?
A thin sheet of aluminum.
What will stop gamma radiation?
A few cm of lead or a few meters of concrete
Order the 3 types if radiation from most to least ionising.
Most: Alpha radiation
Beta radiation
Least: Gamma radiation
State any changes to mass or change that occur due to the emission of a gamma ray.
Both mass and charge remain unchanged.
Describe the nature of radioactive deca.
- Random
- Which nuclei decays and when it decays is determined only by chance
- It is impossible to predict which nuclei will decay and when.
Define half-life of a radioactive isotope.
• The time it takes if the no. of unstable nuclei in a
substance to halve
• The time it takes for the count-rate of a sample to fall
to half its initial level.
What is radioactive contamination?
The presence of unwanted radioactive nuclei ON other materials. The material becomes radioactive.
