A cobalt-60 source used for industrial radiography has an initial activity of

PHYSICS · Multi-part · A Level · Physics · Nuclear physics · Nuclear physics

Problem

4.44\times10^{12}\,\text{Bq}

. The half-life of cobalt-60 is

5.27\,\text{y}

. (i) Express the initial activity in curie (Ci). (ii) Calculate the activity of the source after

21.08\,\text{y}

. (iii) Determine the minimum time (in years) after which the activity will fall below

1.0\,\text{mCi}