Half life Flashcards
Define what is meant by the activity of a sample.
It measures how many atoms in a radioactive isotope decay per second.
How do radioactive substances give out radiation?
From the nuclei of their atoms.
How can radiation be measured?
By a Geiger-Muller tube and counter.
What is half-life?
Finding out the time it takes for the amount of radiation emitted by a source to halve.
How can half-life be used?
It can be used to make predictions about radioactive sources, even though their decays are random.
It can also be used to find the rate at which a source decays-its activity.
What is ‘activity’ measured in?
Becquerels (Bq)(where 1 Bq is one decay per second.)
What happens every time a radioactive nucleus decays to become a stable nucleus?
The activity as a whole will decrease (older sources emit less radiation)
Why is it difficult to measure activity?
Because the activity never reaches zero.
How is the half-life found when using a graph?
It is found by finding the time interval on the bottom axis corresponding to a halving of the activity on the vertical axis
