At 10:00 a.m. the activity of a freshly prepared sample of isotope Y is 8000 Bq. At 12:00 noon the activity has fallen to 3500 Bq.
(i) Assuming Y decays only by a single radioactive process, calculate its half-life.
(ii) Using the half-life obtained in part (i), find the activity expected at 3:30 p.m. the same day.
(iii) A measurement taken at 3:30 p.m. actually gives 3300 Bq. Decide whether this experimental value agrees with the prediction of part (ii) to within 5 %, showing the necessary calculation.