Atoms and nuclear radiation Flashcards
Why do unstable nuclei give out radiation?
- Unstable nuclei undergo decay to become more stable.
- As they release radiation, their stability increases.
What is the name of the process in which an unstable nucleus gives out radiation to become more stable?
Radioactive decay.
Define the activity of an unstable nucleus
Activity is the rate of decay of a source of unstable nuclei.
What is the unit of radioactive decay?
Becquerel (Bq).
What is count-rate?
The number of radioactive decays per second for 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.
- Beta particles.
- Gamma rays.
- Neutrons.
What are the constituents of an alpha particle?
- 2 protons and 2 neutrons.
- It is the same as a helium nuclei.
What is the range of an alpha particle through air?
A few cm (normally in the range of 2-10cm).
What will stop beta radiation from passing through a point?
- A thin sheet of aluminium.
- Several meters of air.
What will stop gamma radiation from passing through a point?
- Several cm of lead.
- A few meters of concrete.
Which type of radiation is most ionising?
Alpha radiation.
Which type of radiation is least ionising?
Gamma radiation.
State any changes to mass or charge that occur due to the emission of gamma ray
Both mass and charge remain unchanged because gamma is radiation/wave (has no mass or charge).
Describe the nature of radioactive decay
- Random.
- Which nuclei decays and when is determined only by chance.
- It is impossible to predict which nuclei will decay and when.
