(a)[1]
From all the measurements obtained, determine a mean value for the background count rate.
(b(i))[1]
Show your answer by placing ticks (✓) in the correct boxes for the radiation emitted by cobalt-60: alpha-particles, beta-particles, gamma rays.
(b(ii).1)[1]
The radiation is emitted when a cobalt-60 nucleus ($^{60}_{27}\text{Co}$) decays to a nucleus of the daughter product X. Product X is not radioactive. Determine how many protons are present in a nucleus of X.
(b(ii).2)[1]
Find the neutron number in a nucleus of X.
(c(i))[2]
The half-life of cobalt-60 is 5.3 years. State the meaning of half-life.
(c(ii))[2]
There are reasons to think that the variation in these readings is random rather than due to the number of cobalt-60 atoms in the sample falling. State two of these reasons.