The half-life of a material is 3 hours.
If the initial count rate is 544 Bq,
what will the count rate be after 15 hours?
Answer.
Put the count rate in boxes and use arrows to represent the half-life.
We are told that the half-life of the material is 3 hours.
In 15 hours there are 15 ÷ 3 half-lives
= 5 half-lives.
After each half-life the count rate is halved.