AQA Chapter 7 Radioactivity

What is meant by background radiation?

• Radiation produced only by radioactive isotopes in hospitals

• Radiation from all around us, including natural and artificial sources

• Radiation that cannot be detected by any device

• Radiation without harmful effects

Which type of radiation is most strongly ionising?

• Gamma

• X-ray

• Beta

• Alpha

When an object is irradiated by radioactive material, it:

• Becomes radioactive itself

• Is temporarily exposed to radiation, but does not become radioactive

• Absorbs neutrons and emits protons

• Can never be used again

Radioactive contamination refers to:

• Unwanted presence of radioactive material on other materials

• Harmless background rays

• Radiation absorbed only by living cells

• All of the above

The use of thick lead barriers when working with radioactive sources is to:

• Keep out oxygen

• Shield from gamma radiation

• Prevent splashing of chemicals

• Make the room darker

Which material best stops beta radiation?

• Thin paper

• Iron nail

• Aluminium foil (about 5mm thick)

• Glass window

The range in air of gamma radiation is:

• Few cm

• A few metres

• Infinite (but intensity reduces with distance)

• 1 metre only

Why is alpha radiation more dangerous inside the body compared to outside?

• It can pass through the skin easily

• Its high ionising power damages cells if inhaled or ingested

• It is very penetrating through lead

• It reflects most tissues

Which application uses a radioactive isotope for thickness monitoring?

• Alpha source

• Beta source

• Gamma source

• Non-radioactive material only

What should workers wear to monitor exposure to ionising radiation?

• Safety goggles

• Film badge or radiation dosimeter

• Lab coat only

• Steel toe boots