Types of nuclear radiationEdexcel International A Level Physics: Mind map

Exam questions on Types of nuclear radiation

1. A student investigates a radioactive source in a school laboratory using a Geiger–Müller tube connected to a counter. Before bringing the source out of its store, she records 120 counts in 10 minutes. With the source placed 5 cm from the tube she then records 1890 counts in 5.0 minutes.
   Explain why the student measures the background count over a long period and what she does with it.2 marks
2. A technician is testing two unlabelled sources, X and Y, using a Geiger–Müller tube about 2 cm away and subtracting the background count rate each time. For source X, the corrected count rate falls to zero when a single sheet of paper is placed in front of the tube. For source Y, a sheet of paper makes no difference, but the corrected count rate falls to zero when a 4 mm thick aluminium plate is placed in front of the tube.
   Explain why the radiation from source X is stopped by paper but the radiation from source Y is not.2 marks
3. Radium-226 (proton number 88) is a naturally occurring alpha emitter that decays to an isotope of radon (Rn). Carbon-14 (proton number 6) is a beta-minus emitter that is used in radiocarbon dating and decays to an isotope of nitrogen (N).
   Complete the nuclear equation for the alpha decay of radium-226: $^{226}_{88}\text{Ra} \rightarrow \ ?\ + \ ?$3 marks