UNIT 6 - HALF-LIFE

Question 1

WHAT IS HALF-LIFE ?

Answer 1

The time taken for half the radioactive nuclei in a sample to decay
Different isotopes have different half lives.

Question 2

DESCRIBE HOW RADIOACTIVITY CAN BE MODELLED ?

Answer 2

Radioactive decay can be modelled using dice
The more dice used the better random decay is represented

Question 3

WHAT IS CARBON DATING ?

Answer 3

Carbon 14 is used in carbon dating
Living things absorb small amounts of carbon 14
After death the amount of C14 in an organism decreases as C14 decays
The amount of C14 remaining in an object can be used to date the object

Question 4

WHAT ARE RADIOACTIVE TRACERS ?

Answer 4

Used for medical imaging. The radioactive material is injected and detectors are placed outside of the body allowing for detailed images to be created.

Question 5

WHAT MUST BE CONSIDERED WHEN PICKING A TRACER ?

Answer 5

• The half-life
  -The penetrating power and biological effect

Short half-life / least ionising

Question 6

WHAT CAN RADIATION BE USED TO TREAT ?

Answer 6

Gamma radiation can be aimed at cancer cells from the outside of the body - Very penetrating but weakly ionising ( Pass through the body but doesn’t kill living cells)
Radioactive material can be placed inside cancer cells, it needs to be strongly ionising so that it kills cancerous cells.