Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Radioactivity and Particles
123 practice questions
Topics covered
Practice questions
121–123 of 123
Question 121
5 marks · Normal
Answer and see the solution →A student investigates the penetration of different types of radiation in a laboratory experiment and learns how radioactive substances can be detected.
(a)[2 marks]Name one instrument that can detect ionising radiation and briefly describe how it works.
(b)[2 marks]The student places a piece of aluminium between a radioactive source and a Geiger-Müller tube. The count rate drops to background level. Explain what this tells you about the type of radiation being emitted and why.
(c)[1 mark]State one unit you would use to record the activity in this investigation.
Question 122
5 marks · Normal
Answer and see the solution →A scientist uses a Geiger-Muller tube to investigate a radioactive isotope in the laboratory. The isotope decays by emitting beta particles. The scientist also uses a stopwatch to record results.
(a)[1 mark]State the unit used to measure the activity of the radioactive isotope.
(b)[2 marks]Explain how the Geiger-Muller tube detects ionising radiation.
(c)[2 marks]Describe what happens to the atomic number and mass number of the isotope after each beta decay.
Question 123
5 marks · Hard
Answer and see the solution →A nuclear reactor uses uranium-235 as a fuel. The uranium-235 nucleus can undergo fission when it absorbs a neutron. The process produces energy, radioactive daughter nuclei, and more neutrons. Control rods and moderators play key roles in the reactor's operation. Some isotopes in the reactor can also emit gamma radiation.
(a)[2 marks]Describe, using nuclear notation if helpful, the basic process of nuclear fission for uranium-235 and why more neutrons are produced in the process.
(b)[2 marks]Explain how a chain reaction is controlled in a nuclear reactor. Your answer should mention the purposes of control rods and the moderator.
(c)[1 mark]One of the fission products emits gamma radiation. Compare the nature and penetration of gamma radiation with that of beta particles.