Atoms and Nuclear radiation

Cards (13)

Why do unstable nuclei give out radiation?
Unstable nuclei undergo radiation to become stable
As they release radiation their stability increases
Define the activity of the unstable nucleus.
Activity is the rate of decay.
What is the unit of radioactive decay?
Becquerel (Bq)
What is count rate?
The number of radioactive decays per second
What can measure count rate?
Geiger-Muller tube
State 4 types of nuclear radiation?
Alpha particles, Beta particles, Gamma ray, Neutrons
What is an alpha particle?
An alpha particle is a helium nucleus; 2 protons, 2 neutrons
Name the penetrating power of the radiations
Lowest
Alpha - A few centimeters (2-10cm)
Beta - A thin sheet of Aluminium
Gamma - Several centimeters of lead
Most
List the radiations in type of ionising power
Least
Gamma
Beta
Alpha
Most
Describe the nature of radioactive decay?
Random
Which nuclei decays and is determined by chance
It is impossible to predict when it happens
Define the half-life of a radioactive isotope.
The time it takes for the number of unstable nuclei in a substance to halve
The time it takes for the count rate to fall to half its level
What is radioactive contamination?
The presence of unwanted radioactive nuclei on materials
What is irradiation?
Exposure to radioactive material, the material does NOT become radioactive