(a)[1]
Estimate the half-life of the radioactive isotope. Use the data in the table.
(b)[1]
For the second experiment the teacher repeats the method using a different sample of the same radioactive isotope. The mass of the second sample is greater than the mass of the first sample. Propose a value for the count rate of this sample at the beginning of the experiment.
(c(i))[1]
Describe the nature of an $\alpha$-particle.
(c(ii))[1]
Describe the ionising ability of an $\alpha$-particle.
(c(iii))[1]
Describe the penetrating ability of an $\alpha$-particle.