A collector of vintage timepieces uses a Geiger-Muller detector and digital counter to measure the radiation emitted by a radium-dial pocket watch over a continuous period of 150 seconds150\text{ seconds}150 seconds.
The counter records a total of 3570 counts3570\text{ counts}3570 counts during this period. The average background radiation count rate in the workshop is determined to be 0.54 counts per second0.54\text{ counts per second}0.54 counts per second.
Calculate the corrected count rate for the pocket watch alone, in counts per second.
The collector also acquires an architectural granite hearthstone with a mass of 64 kg64\text{ kg}64 kg.
Every 1 kg1\text{ kg}1 kg of this granite has a radioactive activity of 185 Bq185\text{ Bq}185 Bq.
Calculate the total activity of the hearthstone in Bq\text{Bq}Bq.
16 exam-style questions on AQA GCSE Physics 4.3 Hazards and uses of radioactive emissions and of background radiation, covering 4.3.1 Background radiation, 4.3.2 Different half-lives of radioactive isotopes, and 4.3.3 Uses of nuclear radiation. Each one has a worked solution and a mark scheme showing where the marks go.