A radiation detector in a physics laboratory measures a background count rate of 20 counts/min20\text{ counts/min}20 counts/min. A radioactive source is placed in front of the detector, and the initial reading on the detector is 340 counts/min340\text{ counts/min}340 counts/min. The half-life of this radioactive source is 18 minutes18\text{ minutes}18 minutes.
Calculate the expected reading on the detector after 54 minutes54\text{ minutes}54 minutes.
Describe how the proton number and the nucleon number of a nucleus change when it undergoes β−\beta^-β−-decay.
State one safety precaution that should be taken when handling or storing radioactive sources in a laboratory.
144 exam-style questions on CIE IGCSE Physics 5.2.4a Half-life. Each one has a worked solution and a mark scheme showing where the marks go.