Radioactive decay

A sample of a radioactive isotope gives a count rate of $10\,000$ counts per minute. The half-life of the isotope is one day. What was the count rate of the sample two days ago?

May/June 2016

The diagram illustrates a nuclear reaction. The shaded particles have no charge. What products are shown in this reaction?

Oct/Nov 2018

Lead isotope $^{{212}}_{{82}}\text{Pb}$ is radioactive. Following three decays, two beta-particles and one alpha-particle are emitted. A different radioactive lead isotope is then produced. What is the mass number (nucleon number) of this new isotope of lead?

Oct/Nov 2019

Table 7.1 gives the make-up of four neutral atoms together with one atom that has been ionised. The five particles are named P, Q, R, S and T.

Oct/Nov 2019

Every isotope of radon is radioactive.

Oct/Nov 2019