Uses of Radiation Flashcards

All 5 cards in this deck

What type of source is used in a household fire (smoke) alarm, and how does it work?

An alpha emitter: alpha ionises the air so a small current flows; smoke absorbs the alpha, the current drops and the alarm sounds.

True or false? Food that has been irradiated with gamma rays becomes radioactive.

False. Irradiation kills bacteria so the food keeps longer, but leaves no radioactive material in the food.

Why is gamma radiation used to sterilise medical equipment?

It kills bacteria and other microorganisms, and is penetrating enough to work through sealed packaging without heating the equipment.

Which type of source is used to gauge the thickness of paper or metal foil, and why?

A beta emitter: some beta passes through, so the count rate reaching the detector changes if the thickness changes.

Which type of source is used as a tracer to find a leak in an underground pipe, and why?

A gamma emitter, because gamma can penetrate the pipe and soil to be detected at the surface above the leak.