Half-life Flashcards
1
Q
What is the Half-life of a radioactive substance?
A
The average time it takes for the number of nuclei (in an isotope) to halve.
2
Q
What radioactive substance can be used to identify ancient materials?
A
Carbon-14
3
Q
What are the 2 main medical uses of radioactive substances?
A
Radio-imaging- Gamma emitters are injected into the body and make their way to a specific area. Gamma rays can then be detected from outside the body.
Radiotherapy- Beta emitters are injected to kill affected (usually cancerous) areas as they have a short range in flesh.
4
Q
What 3 properties can decide whether a radioactive substance is used?
A
Half-life
Ionising Power
Penetrative power
5
Q
What is the unit for radioactive decay what does it mean?
A
Becquerel (Bq)- radioactive decay per second.
