4.4.3 - Hazards and Uses of Radioactive Emissions and Background Radiation (Physics Only)

Atomic Structure

Give 4 sources of background radiation.

1. Rocks
2. Cosmic rays from space
3. Nuclear weapon testing
4. Nuclear accidents

How should background radiation be dealt with in calculations?

The background count should be subtracted from any readings before calculations (half life etc.) are attempted

What is the unit used to measure radiation dosage?

Sieverts (Sv)

How many millisieverts equal 1 sievert?

1000 millisieverts = 1 sievert

Why might the radiation dosage that different people experience differ?

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

What factor determines how dangerous a particular radioactive isotope is?

The half-life of the isotope

Why are isotopes with long half-lives particularly harmful?

They remain radioactive for much longer periods of time

They must be stored in specific ways to avoid humans and the environment from being exposed to radiation for too long

State two uses of nuclear radiation in the field of medicine.

1. Examining of internal organs
2. Controlling and destroying unwanted tissue

How is radiation used in sterilisation?

Gamma emitters are used to kill bacteria/parasites on equipment.

Explain the process of radiotherapy.

Gamma emitters direct gamma rays at the cancerous cells

The cancerous cells absorb the radiation and are killed

How are medical tracers chosen?

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

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