Le 2011/04/15 13:48, Orchid XP v8 a écrit :

>> Halflife is defined as "the time it takes for half of the original
>> amount to degrade". So, it takes 700 millions years for half of your
>> uranium's atoms to deckay, and thus, emit radiation. After 1400 millions
>> years, 75% of the original amount will have deckayed.
>> It apply to radioactive materials. It also apply to medication in your
>> body, and many other things.
>
> Are you saying there's some sort of relationship between the halflife of
> a substance and how much radiation it emits?
>

Not some sort of relation. Direct relation.
The rate of emission is directly proportional to the amount and invertly 
proportional to the halflife.

A substance that have a halflife of 1 year is 700 millions times more 
radioactive than uranium. Some radioactive materials have halflife of 
much less than a second, like about 1e-10s. This makes them 
extraordinary radioactive, but you can never accumulate more than a few 
femtograms of them at any given time...


Alain

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