Half-life Flashcards
What is Half-life?
Half-life it the time taken for half of the radioactive atoms now present to decay.
The time it takes for a radioactive material to lose half of its radioactivity.
(the radioactivity of a sample always decreases over time).
Why does the radioactivity of a sample always decrease over time?
Each time a decay happens and an alpha or beta particle or gamma ray is given out, it means one more radioactive nucleus has disappeared.
What is meant by a short half-life?
the activity falls quickly, because lots of the nuclei decay quickly.
What is meant by a long half-life?
The activity falls slowly because most of the nuclei don’t decay for a long time - they just sit there, basically unstable, but kind of biding their time.
For any particular isotope, the half-life is….
….the same.
