6.5 Radioactive half life?

Question 1

How do you measure the radioactivity of a sample of radioactive material ?

Answer 1

By measuring the count rate.

Question 2

What is the half life of a radioactive isotope

Answer 2

The average time it take for the number of nuclei of the isotope in a sample to halve

Question 3

What happens to the original count rate of a radioactive sample after two half lives have passed?

Answer 3

It has decreased to one quarter of its original value