T4 hazards and uses of radioactive emissions and background radiation

Question 1

give 4 sources of background radiation

Answer 1

1. rocks
2. cosmic rays from space
3. nuclear weapon testing
4. nuclear accidents

Question 2

how should background radiation be dealt within calculations

Answer 2

background count should be subtracted from any reading before calculations are attempted

Question 3

unit used to measure radiation dosage

Answer 3

sieverts (Sv)

Question 4

how many millisieverts equal 1 sievert

Answer 4

1000 millisieverts = 1 sievert

Question 5

why might the radiation dosage that different people experience differ

Answer 5

• some occupations involve working with radiation
• background radiation differs with location due to things such as the locality of nuclear power stations or radiation related testing

Question 6

what factor determines how dangerous a particular radioactive isotope is

Answer 6

half-life of the isotope

Question 7

why are isotopes with long half-lives particularly harmful

Answer 7

• remain radioactive for much longer periods of time

- must be stored in specific ways to avoid humans and the environment for too long

Question 8

state 2 uses of nuclear radiation in the field of medicine

Answer 8

1. examining of internal organs

2. controlling and destroying unwanted tissue

Question 9

how is radiation used in sterilisation

Answer 9

gamma emitters are used to kill bacteria/parasites on equipment

Question 10

explain the process of radiotherapy

Answer 10

• gamma emitters direct gamma rays at the cancerous cells

- cancerous cells absorb the radiation and are killed

Question 11

how are medical tracers chosen

Answer 11

should have a short half life and decay into a stable isotope which can be excreted

should only release gamma radiation since it is weakly ionising and can easily pass through body tissue without damaging it