Half-life

Question 1

What is Half-life?

Answer 1

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).

Question 2

Why does the radioactivity of a sample always decrease over time?

Answer 2

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.

Question 3

What is meant by a short half-life?

Answer 3

the activity falls quickly, because lots of the nuclei decay quickly.

Question 4

What is meant by a long half-life?

Answer 4

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.

Question 5

For any particular isotope, the half-life is….

Answer 5

….the same.