Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Radioactivity and Particles
123 practice questions
Topics covered
Practice questions
31–40 of 59 · Normal
Question 31
5 marks · Normal
Answer and see the solution →A student investigates the decay of a radioactive isotope by measuring its activity (in Bq). The data below shows the measured activity at 10-minute intervals, after correcting for background radiation.
Radioactive decay data Time (min) Activity (Bq) 0 480 10 240 20 120 30 60 (a)[1 mark]Describe what is meant by the half-life of a radioactive isotope.
(b)[2 marks]Use the table to determine the half-life of this isotope. Show your working.
(c)[2 marks]Explain why the measured activity falls as time passes.
Question 32
4 marks · Normal
Answer and see the solution →This question is about nuclear fission in uranium-235.
(a)[1 mark]State the meaning of the term 'fission' as used in nuclear physics.
(b)[2 marks]Describe what happens when a uranium-235 nucleus absorbs a slow-moving neutron.
(c)[1 mark]Name the type of energy released as a direct result of the fission reaction.
Question 33
3 marks · Normal
Answer and see the solution →In the fission of uranium-235, different numbers of neutrons can be released depending on the fission event. The table below shows data from five fission events.
Number of neutrons released in five different uranium-235 fission events. Fission event Number of neutrons released 1 2 2 3 3 3 4 2 5 4 (a)[2 marks]Calculate the average number of neutrons released per fission event in this sample.
(b)[1 mark]Explain why the actual number of neutrons released per fission can vary between events.
Question 34
1 mark · Normal
Answer and check →Which of the following is NOT a product of uranium-235 fission?
- A.barium-144
- B.krypton-89
- C.proton
- D.neutron
Question 35
2 marks · Normal
Answer and see the solution →Name and briefly describe the function of two components used to control the rate of fission reactions in a nuclear reactor.
Question 36
3 marks · Normal
Answer and see the solution →Explain why shielding is needed around a nuclear reactor. Give two reasons.
Question 37
3 marks · Normal
Answer and see the solution →Describe how a chain reaction is produced in a nuclear reactor using uranium-235.
Question 38
4 marks · Normal
Answer and see the solution →Consider the following nuclear fission equation for uranium-235:
Answer the following questions about it.
(a)[1 mark]How many neutrons are produced in this fission reaction?
(b)[3 marks]Verify that both mass and atomic numbers are conserved on both sides of the equation.
Question 39
3 marks · Normal
Answer and see the solution →Some of the energy released in nuclear fission leaves the reactor as electromagnetic radiation. Explain why most of the energy from fission comes from the kinetic energy of the products rather than from electromagnetic radiation.
Question 40
4 marks · Normal
Answer and see the solution →Nuclear reactions can involve either fission or fusion.
(a)[2 marks]State one similarity and one difference between nuclear fission and nuclear fusion.
(b)[2 marks]Explain why nuclear fusion requires much higher temperatures and pressures than fission.