(a(i))[1]
Suggest a source of these readings.
(a(ii))[1]
Explain why the count-rate readings do not stay constant.
(b)[3]
Complete the nuclide equation for this radioactive decay. $^{\;\;}\text{U} \rightarrow ^{\;\;}\text{Th} + ^{\;\;}\alpha$
(c)[2]
Calculate the time needed for 16 mg of this isotope to decay to 2 mg of this isotope.