Radioactivity Flashcards
Alpha tracks in cloud chamber
All same length
Straight and easily visible
Beta tracks in cloud chamber
Wispy tracks and are easily deflected by air molecules
More difficult to see as they are less ionising than alpha
Why does absorption test graph level out
Beta is being absorbed and gamma starts getting released
What is a Geiger tube
Sealed metal tube containing argon gas at low pressure
Walls are if negative potential and earthed
Metal rod down centre is of positive potential
How does Geiger counter work
Ionising radiation that enters and ionises gas its path
These ions collide with each other and other atoms creating more ions
All the ions discharge at the electrodes and the voltage pulse across R is recorded as one count
Damages of radioactivity
DUM
Die
Uncontrollably grow
Mutate
What is a film badge and how does it work
Photographic film covered in different absorbers of different materials and thicknesses in different areas
When the film is developed the amount of exposure can be estimated from the blackening of the film
What is a half life
Time taken for the mass of an isotope to decrease to half the initial mass
What is the activity of a radioactive isotope
The number of nuclei of the isotope that disintegrate per second
Measured in Becquels (Bq)
Carbon dating
Measuring the activity of a sample of carbon from a dead tree we can estimate its age
Carbon 14 half life and where it comes from
5770 years
Cosmic rays knocking out neutrons from nuclei
These nuclei collide with nitrogen nuclei to create carbon 14
Argon dating
Radioactive isotope 40K19 decays into 40Ar18 through electron capture and this is a gas trapped in ancient rocks
The age of the rock can be calculated by comparing the proportion of argon40 to potassium40
Half life of potassium40
1.25 billion years
What happens in neutron rich nuclei
Beta minus decay
What happens in proton rich nuclei
Beta plus decay
What is a meta stable state
A long lived excited state
What is technetium generator used for
A source of gamma radiation
Nuclear radius equation
R=(r0)A^(1/3)
