Half-life

Radioactivity is a Totally random process

Radioactive substances give out radiation from the nuclei of there atoms no matter what.

This radiaion can be measured with a Geiger-Muller tube and counter, which records the count-rate -- the number of radiation counts reaching it per second.

Radioactive decay is entirely random. So you can't predict exactly which nucleus in a sample will decay next, or when any of them will decay. 

But you can find out the time it takes for the amount of radiation emmited by a source of halve, this is known as the half-life. It can be used to make predictions about radioactive sources, even though their decay are random. 

Half-life can be used to find the rate at which a source decays. Activity is measured in becquerels, BQ (when 1 BQ is one decay per second)

Each time a radioactive nuccleus decays it becomes a…