R6 - Half Life Flashcards Preview

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Flashcards in R6 - Half Life Deck (9):

What happens to a sample of radioactivity over time?

It decreases


What happens each time an alpha or beta or gamma particle is given out?

One more radioactive nucleus has disappeared


What happens as the unstable nuclei all disappears?

The activity as a whole decreases as the older the sample gets, the less radiation it will emit


What is the problem with trying to measure how quickly the activity drops off?

It varies for some isotopes and the activity never reaches zero which is why we use to idea of a half life


What is a half life?

The time it takes for half of the radioactive atom to decay


What does a short and long half-life means?

Short half life - activity falls quickly because lots of nuclei decay quickly

Long half life - activity falls more slowly because most of the unstable nuclei dont decay for a long time


How can you measure the half life of a sample using a graph?

Can only be done by talking several readings of a source activity usually using a Geiger-Muller detector


How is the half life found from a graph?

Find the time interval on the bottom axis corresponding to a halving of the activity on the vertical axis


What should you do with the background radiation that also enters the GM detector?

First measure the background radiation then subtract it from every reading you get